Better docs structure and minor fixes

docs/guide/database-basics.md

@@ -9,8 +9,8 @@ uniform API and solves some inconsistencies between different DBMS. By default Y
 - [SQLite](http://sqlite.org/)
 - [PostgreSQL](http://www.postgresql.org/)
 - [CUBRID](http://www.cubrid.org/) (version 9.1.0 and higher).
-- Oracle
-- MSSQL
+- [Oracle](http://www.oracle.com/us/products/database/overview/index.html)
+- [MSSQL](https://www.microsoft.com/en-us/sqlserver/default.aspx)
 
 
 Configuration
@@ -42,6 +42,7 @@ return [
 	// ...
 ];
 ```
+
 Please refer to the [PHP manual](http://www.php.net/manual/en/function.PDO-construct.php) for more details
 on the format of the DSN string.
 

docs/guide/debugger.md

@@ -7,19 +7,21 @@ about currently opened page while using debugger you can analyze data collected
 Installing and configuring
 --------------------------
 
-How to use it
--------------
-
 Add these lines to your config file:
 
 ```
-    'preload' => ['debug'],
-    'modules' => [
-            'debug' => ['yii\debug\Module']
-        ]
+'preload' => ['debug'],
+'modules' => [
+	'debug' => ['yii\debug\Module']
+]
 ```
 
-**Watch out: by default the debug module only works when browsing the website from the localhost. If you want to use it on a remote (staging) server, add the parameter allowedIPs to the config to whitelist your IP.**
+**Watch out: by default the debug module only works when browsing the website from the localhost. If you want to use it
+on a remote (staging) server, add the parameter allowedIPs to the config to whitelist your IP.**
+
+How to use it
+-------------
+
 
 Creating your own panels
 ------------------------

docs/guide/gii.md

@@ -7,17 +7,17 @@ as well as complete CRUD controllers.
 Installing and configuring
 --------------------------
 
-How to use it
--------------
-
 Add these lines to your config file:
 
 ```php
-    'modules' => [
-            'gii' => ['yii\gii\Module']
-        ]
+'modules' => [
+	'gii' => ['yii\gii\Module']
+]
 ```
 
+How to use it
+-------------
+
 Creating your own templates
 ---------------------------
 

docs/guide/i18n.md

@@ -264,3 +264,5 @@ Formatters
 
 In order to use formatters you need to install and enable [intl](http://www.php.net/manual/en/intro.intl.php) PHP
 extension.
+
+TBD: provided classes overview.