diff --git a/docs/guide/database-basics.md b/docs/guide/database-basics.md
index ade5968..71510f4 100644
--- a/docs/guide/database-basics.md
+++ b/docs/guide/database-basics.md
@@ -25,7 +25,7 @@ return array(
 			//'dsn' => 'sqlsrv:Server=localhost;Database=mydatabase', // MS SQL Server, sqlsrv driver
 			//'dsn' => 'dblib:host=localhost;dbname=mydatabase', // MS SQL Server, dblib driver
 			//'dsn' => 'mssql:host=localhost;dbname=mydatabase', // MS SQL Server, mssql driver
-			//'dsn' => 'oci:dbname=//localhost:1521/testdb', // Oracle
+			//'dsn' => 'oci:dbname=//localhost:1521/mydatabase', // Oracle
 			'username' => 'root',
 			'password' => '',
 			'charset' => 'utf8',
diff --git a/docs/guide/query-builder.md b/docs/guide/query-builder.md
index e69de29..c707ddda6 100644
--- a/docs/guide/query-builder.md
+++ b/docs/guide/query-builder.md
@@ -0,0 +1,235 @@
+Query Builder and Query
+=======================
+
+Yii provides a basic database access layer as was described in [Database basics](database-basics.md) section. Still it's
+a bit too much to use SQL directly all the time. To solve the issue Yii provides a query builder that allows you to
+work with the database in object-oriented style.
+
+Basic query builder usage is the following:
+
+```php
+$query = new Query;
+
+// Define query
+$query->select('id, name')
+ 	->from('tbl_user')
+ 	->limit(10);
+
+// Create a command. You can get the actual SQL using $command->sql
+$command = $query->createCommand();
+// Execute command
+$rows = $command->queryAll();
+```
+
+Basic selects and joins
+-----------------------
+
+In order to form a `SELECT` query you need to specify what to select and where to select it from.
+
+```php
+$query->select('id, name')
+	->from('tbl_user');
+```
+
+If you want to get IDs of all users with posts you can use `DISTINCT`. With query builder it will look like the following:
+
+```php
+$query->select('user_id')->distinct()->from('tbl_post');
+```
+
+Select options can be specified as array. It's especially useful when these are formed dynamically.
+
+```php
+$query->select(array('tbl_user.name AS author', 'tbl_post.title as title')) // <-- specified as array
+	->from('tbl_user')
+	->leftJoin('tbl_post', 'tbl_post.user_id = tbl_user.id'); // <-- join with another table
+```
+
+In the code above we've used `leftJoin` method to select from two related tables at the same time. Firsrt parameter
+specifies table name and the second is the join condition. Query builder has the following methods to join tables:
+
+- `innerJoin`
+- `leftJoin`
+- `rightJoin`
+
+If your data storage supports more types you can use generic `join` method:
+
+```php
+$query->join('FULL OUTER JOIN', 'tbl_post', 'tbl_post.user_id = tbl_user.id');
+```
+
+Specifying conditions
+---------------------
+
+Usually you need data that matches some conditions. There are some useful methods to specify these and the most powerful
+is `where`. There are multiple ways to use it.
+
+The simplest is to specify condition in a string:
+
+```php
+$query->where('status=:status', array(
+	':status' => $status,
+));
+```
+
+When using this format make sure you're binding parameters and not creating a query by string concatenation.
+
+Instead of binding status value immediately you can do it using `params` or `addParams`:
+
+```php
+$query->where('status=:status');
+
+$query->addParams(array(
+	':status' => $status,
+));
+```
+
+There is another convenient way to use the method called hash format:
+
+```php
+$query->where(array(
+	'status' => 10,
+	'type' => 2,
+	'id' => array(4, 8, 15, 16, 23, 42),
+));
+```
+
+It will generate the following SQL:
+
+```sql
+WHERE (`status` = 10) AND (`type` = 2) AND (`id` IN (4, 8, 15, 16, 23, 42))
+```
+
+If you'll specify value as `null` such as the following:
+
+```php
+$query->where(array(
+	'status' => null,
+));
+```
+
+SQL generated will be:
+
+```sql
+WHERE (`status` IS NULL)
+```
+
+Another way to use the method is the operand format which is `array(operator, operand1, operand2, ...)`.
+
+Operator can be one of the following:
+
+- `and`: the operands should be concatenated together using `AND`. For example,
+  `array('and', 'id=1', 'id=2')` will generate `id=1 AND id=2`. If an operand is an array,
+  it will be converted into a string using the rules described here. For example,
+  `array('and', 'type=1', array('or', 'id=1', 'id=2'))` will generate `type=1 AND (id=1 OR id=2)`.
+  The method will NOT do any quoting or escaping.
+- `or`: similar to the `and` operator except that the operands are concatenated using `OR`.
+- `between`: operand 1 should be the column name, and operand 2 and 3 should be the
+   starting and ending values of the range that the column is in.
+   For example, `array('between', 'id', 1, 10)` will generate `id BETWEEN 1 AND 10`.
+- `not between`: similar to `between` except the `BETWEEN` is replaced with `NOT BETWEEN`
+  in the generated condition.
+- `in`: operand 1 should be a column or DB expression, and operand 2 be an array representing
+  the range of the values that the column or DB expression should be in. For example,
+  `array('in', 'id', array(1, 2, 3))` will generate `id IN (1, 2, 3)`.
+  The method will properly quote the column name and escape values in the range.
+- `not in`: similar to the `in` operator except that `IN` is replaced with `NOT IN` in the generated condition.
+- `like`: operand 1 should be a column or DB expression, and operand 2 be a string or an array representing
+  the values that the column or DB expression should be like.
+  For example, `array('like', 'name', '%tester%')` will generate `name LIKE '%tester%'`.
+  When the value range is given as an array, multiple `LIKE` predicates will be generated and concatenated
+  using `AND`. For example, `array('like', 'name', array('%test%', '%sample%'))` will generate
+  `name LIKE '%test%' AND name LIKE '%sample%'`.
+  The method will properly quote the column name and escape values in the range.
+- `or like`: similar to the `like` operator except that `OR` is used to concatenate the `LIKE`
+  predicates when operand 2 is an array.
+- `not like`: similar to the `like` operator except that `LIKE` is replaced with `NOT LIKE`
+  in the generated condition.
+- `or not like`: similar to the `not like` operator except that `OR` is used to concatenate
+  the `NOT LIKE` predicates.
+
+If you are building parts of condition dynamically it's very convenient to use `andWhere` and `orWhere`:
+
+```php
+$status = 10;
+$search = 'yii';
+
+$query->where(array('status' => $status));
+if (!empty($search)) {
+	$query->addWhere('like', 'title', $search);
+}
+```
+
+In case `$search` isn't empty the following SQL will be generated:
+
+```sql
+WHERE (`status` = 10) AND (`title` LIKE '%yii%')
+```
+
+Order
+-----
+
+For odering results `orderBy` and `addOrderBy` could be used:
+
+```php
+$query->orderBy(array(
+	'id' => Query::SORT_ASC,
+	'name' => Query::SORT_DESC,
+));
+```
+
+Here we are ordering by `id` ascending and then by `name` descending.
+
+Group and Having
+----------------
+
+In order to add `GROUP BY` to generated SQL you can use the following:
+
+```php
+$query->groupBy('id, status');
+```
+
+If you want to add another field after using `groupBy`:
+
+```php
+$query->addGroupBy(array('created_at', 'updated_at'));
+```
+
+To add a `HAVING` condition the corresponding `having` method and its `andHaving` and `orHaving` can be used. Parameters
+for these are similar to the ones for `where` methods group:
+
+```php
+$query->having(array('status' => $status));
+```
+
+Limit and offset
+----------------
+
+To limit result to 10 rows `limit` can be used:
+
+```php
+$query->limit(10);
+```
+
+To skip 100 fist rows use:
+
+```php
+$query->offset(100);
+```
+
+Union
+-----
+
+`UNION` in SQL adds results of one query to results of another query. Columns returned by both queries should match.
+In Yii in order to build it you can first form two query objects and then use `union` method:
+
+```php
+$query = new Query;
+$query->select("id, 'post' as type, name")->from('tbl_post')->limit(10);
+
+$anotherQuery = new Query;
+$query->select('id, 'user' as type, name')->from('tbl_user')->limit(10);
+
+$query->union($anotherQuery);
+```
+
diff --git a/docs/guide/validation.md b/docs/guide/validation.md
index e69de29..7bfeb96 100644
--- a/docs/guide/validation.md
+++ b/docs/guide/validation.md
@@ -0,0 +1,28 @@
+Model validation reference
+==========================
+
+This guide section doesn't describe how validation works but instead describes all Yii validators and their parameters.
+In order to learn model validation basics please refer to [Model, Validation subsection](model.md#Validation).
+
+Standard Yii validators
+-----------------------
+
+- `boolean`: [[BooleanValidator]]
+- `captcha`: [[CaptchaValidator]]
+- `compare`: [[CompareValidator]]
+- `date`: [[DateValidator]]
+- `default`: [[DefaultValueValidator]]
+- `double`: [[NumberValidator]]
+- `email`: [[EmailValidator]]
+- `exist`: [[ExistValidator]]
+- `file`: [[FileValidator]]
+- `filter`: [[FilterValidator]]
+- `in`: [[RangeValidator]]
+- `integer`: [[NumberValidator]]
+- `match`: [[RegularExpressionValidator]]
+- `required`: [[RequiredValidator]]
+- `string`: [[StringValidator]]
+- `unique`: [[UniqueValidator]]
+- `url`: [[UrlValidator]]
+
+TBD: refer to http://www.yiiframework.com/wiki/56/ for the format
\ No newline at end of file
diff --git a/extensions/mutex/composer.json b/extensions/mutex/composer.json
new file mode 100644
index 0000000..db8cde3
--- /dev/null
+++ b/extensions/mutex/composer.json
@@ -0,0 +1,27 @@
+{
+	"name": "yiisoft/yii2-mutex",
+	"description": "Mutual exclusion extension for the Yii framework",
+	"keywords": ["yii", "mutex"],
+	"type": "library",
+	"license": "BSD-3-Clause",
+	"support": {
+		"issues": "https://github.com/yiisoft/yii2/issues?state=open",
+		"forum": "http://www.yiiframework.com/forum/",
+		"wiki": "http://www.yiiframework.com/wiki/",
+		"irc": "irc://irc.freenode.net/yii",
+		"source": "https://github.com/yiisoft/yii2"
+	},
+	"authors": [
+		{
+			"name": "resurtm",
+			"email": "resurtm@gmail.com"
+		}
+	],
+	"minimum-stability": "dev",
+	"require": {
+		"yiisoft/yii2": "*"
+	},
+	"autoload": {
+		"psr-0": { "yii\\mutex": "" }
+	}
+}
diff --git a/extensions/mutex/yii/mutex/DbMutex.php b/extensions/mutex/yii/mutex/DbMutex.php
new file mode 100644
index 0000000..3699c36
--- /dev/null
+++ b/extensions/mutex/yii/mutex/DbMutex.php
@@ -0,0 +1,41 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\mutex;
+
+use Yii;
+use yii\db\Connection;
+use yii\base\InvalidConfigException;
+
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
+abstract class DbMutex extends Mutex
+{
+	/**
+	 * @var Connection|string the DB connection object or the application component ID of the DB connection.
+	 * After the Mutex object is created, if you want to change this property, you should only assign
+	 * it with a DB connection object.
+	 */
+	public $db = 'db';
+
+	/**
+	 * Initializes generic database table based mutex implementation.
+	 * @throws InvalidConfigException if [[db]] is invalid.
+	 */
+	public function init()
+	{
+		parent::init();
+		if (is_string($this->db)) {
+			$this->db = Yii::$app->getComponent($this->db);
+		}
+		if (!$this->db instanceof Connection) {
+			throw new InvalidConfigException('Mutex::db must be either a DB connection instance or the application component ID of a DB connection.');
+		}
+	}
+}
diff --git a/extensions/mutex/yii/mutex/FileMutex.php b/extensions/mutex/yii/mutex/FileMutex.php
new file mode 100644
index 0000000..4a949d0
--- /dev/null
+++ b/extensions/mutex/yii/mutex/FileMutex.php
@@ -0,0 +1,86 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\mutex;
+
+use Yii;
+use yii\base\InvalidConfigException;
+
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
+class FileMutex extends Mutex
+{
+	/**
+	 * @var string the directory to store mutex files. You may use path alias here.
+	 * If not set, it will use the "mutex" subdirectory under the application runtime path.
+	 */
+	public $mutexPath = '@runtime/mutex';
+	/**
+	 * @var resource[] stores all opened lock files. Keys are lock names and values are file handles.
+	 */
+	private $_files = array();
+
+
+	/**
+	 * Initializes mutex component implementation dedicated for UNIX, GNU/Linux, Mac OS X, and other UNIX-like
+	 * operating systems.
+	 * @throws InvalidConfigException
+	 */
+	public function init()
+	{
+		if (stripos(php_uname('s'), 'win') === 0) {
+			throw new InvalidConfigException('FileMutex does not have MS Windows operating system support.');
+		}
+		$this->mutexPath = Yii::getAlias($this->mutexPath);
+		if (!is_dir($this->mutexPath)) {
+			mkdir($this->mutexPath, 0777, true);
+		}
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Acquires lock by given name.
+	 * @param string $name of the lock to be acquired.
+	 * @param integer $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 */
+	protected function acquireLock($name, $timeout = 0)
+	{
+		$file = fopen($this->mutexPath . '/' . md5($name) . '.lock', 'w+');
+		if ($file === false) {
+			return false;
+		}
+		$waitTime = 0;
+		while (!flock($file, LOCK_EX | LOCK_NB)) {
+			$waitTime++;
+			if ($waitTime > $timeout) {
+				fclose($file);
+				return false;
+			}
+			sleep(1);
+		}
+		$this->_files[$name] = $file;
+		return true;
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 */
+	protected function releaseLock($name)
+	{
+		if (!isset($this->_files[$name]) || !flock($this->_files[$name], LOCK_UN)) {
+			return false;
+		} else {
+			fclose($this->_files[$name]);
+			unset($this->_files[$name]);
+			return true;
+		}
+	}
+}
diff --git a/extensions/mutex/yii/mutex/Mutex.php b/extensions/mutex/yii/mutex/Mutex.php
new file mode 100644
index 0000000..297abaf
--- /dev/null
+++ b/extensions/mutex/yii/mutex/Mutex.php
@@ -0,0 +1,95 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\mutex;
+
+use Yii;
+use yii\base\Component;
+
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
+abstract class Mutex extends Component
+{
+	/**
+	 * @var boolean whether all locks acquired in this process (i.e. local locks) must be released automagically
+	 * before finishing script execution. Defaults to true. Setting this property to true means that all locks
+	 * acquire in this process must be released in any case (regardless any kind of errors or exceptions).
+	 */
+	public $autoRelease = true;
+	/**
+	 * @var string[] names of the locks acquired in the current PHP process.
+	 */
+	private $_locks = array();
+
+
+	/**
+	 * Initializes the mutex component.
+	 */
+	public function init()
+	{
+		if ($this->autoRelease) {
+			$mutex = $this;
+			$locks = &$this->_locks;
+			register_shutdown_function(function () use ($mutex, &$locks) {
+				foreach ($locks as $lock) {
+					$mutex->release($lock);
+				}
+			});
+		}
+	}
+
+	/**
+	 * @param string $name of the lock to be acquired. Must be unique.
+	 * @param integer $timeout to wait for lock to be released. Defaults to zero meaning that method will return
+	 * false immediately in case lock was already acquired.
+	 * @return boolean lock acquiring result.
+	 */
+	public function acquire($name, $timeout = 0)
+	{
+		if ($this->acquireLock($name, $timeout)) {
+			$this->_locks[] = $name;
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * Release acquired lock. This method will return false in case named lock was not found.
+	 * @param string $name of the lock to be released. This lock must be already created.
+	 * @return boolean lock release result: false in case named lock was not found..
+	 */
+	public function release($name)
+	{
+		if ($this->releaseLock($name)) {
+			$index = array_search($name, $this->_locks);
+			if ($index !== false) {
+				unset($this->_locks[$index]);
+			}
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Acquires lock by given name.
+	 * @param string $name of the lock to be acquired.
+	 * @param integer $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 */
+	abstract protected function acquireLock($name, $timeout = 0);
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 */
+	abstract protected function releaseLock($name);
+}
diff --git a/extensions/mutex/yii/mutex/MysqlMutex.php b/extensions/mutex/yii/mutex/MysqlMutex.php
new file mode 100644
index 0000000..b04427a
--- /dev/null
+++ b/extensions/mutex/yii/mutex/MysqlMutex.php
@@ -0,0 +1,57 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\mutex;
+
+use Yii;
+use yii\base\InvalidConfigException;
+
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
+class MysqlMutex extends Mutex
+{
+	/**
+	 * Initializes MySQL specific mutex component implementation.
+	 * @throws InvalidConfigException if [[db]] is not MySQL connection.
+	 */
+	public function init()
+	{
+		parent::init();
+		if ($this->db->driverName !== 'mysql') {
+			throw new InvalidConfigException('In order to use MysqlMutex connection must be configured to use MySQL database.');
+		}
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Acquires lock by given name.
+	 * @param string $name of the lock to be acquired.
+	 * @param integer $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 * @see http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_get-lock
+	 */
+	protected function acquireLock($name, $timeout = 0)
+	{
+		return (boolean)$this->db
+			->createCommand('SELECT GET_LOCK(:name, :timeout)', array(':name' => $name, ':timeout' => $timeout))
+			->queryScalar();
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 * @see http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
+	 */
+	protected function releaseLock($name)
+	{
+		return (boolean)$this->db
+			->createCommand('SELECT RELEASE_LOCK(:name)', array(':name' => $name))
+			->queryScalar();
+	}
+}
diff --git a/framework/yii/helpers/base/SecurityHelper.php b/framework/yii/helpers/base/SecurityHelper.php
index f646a24..546ed21 100644
--- a/framework/yii/helpers/base/SecurityHelper.php
+++ b/framework/yii/helpers/base/SecurityHelper.php
@@ -186,7 +186,7 @@ class SecurityHelper
 	 * // ...save $hash in database...
 	 *
 	 * // during login, validate if the password entered is correct using $hash fetched from database
-	 * if (SecurityHelper::verifyPassword($password, $hash) {
+	 * if (SecurityHelper::validatePassword($password, $hash) {
 	 *     // password is good
 	 * } else {
 	 *     // password is bad
diff --git a/framework/yii/web/Response.php b/framework/yii/web/Response.php
index 5b15fbb..1e594aa 100644
--- a/framework/yii/web/Response.php
+++ b/framework/yii/web/Response.php
@@ -557,6 +557,12 @@ class Response extends \yii\base\Response
 	 * });
 	 * ~~~
 	 *
+	 * In a controller action you may use this method like this:
+	 *
+	 * ~~~
+	 * return Yii::$app->getResponse()->redirect($url);
+	 * ~~~
+	 *
 	 * @param array|string $url the URL to be redirected to. [[\yii\helpers\Html::url()]]
 	 * will be used to normalize the URL. If the resulting URL is still a relative URL
 	 * (one without host info), the current request host info will be used.
@@ -584,6 +590,13 @@ class Response extends \yii\base\Response
 	 * Refreshes the current page.
 	 * The effect of this method call is the same as the user pressing the refresh button of his browser
 	 * (without re-posting data).
+	 *
+	 * In a controller action you may use this method like this:
+	 *
+	 * ~~~
+	 * return Yii::$app->getResponse()->refresh();
+	 * ~~~
+	 *
 	 * @param string $anchor the anchor that should be appended to the redirection URL.
 	 * Defaults to empty. Make sure the anchor starts with '#' if you want to specify it.
 	 * @return Response the response object itself