using external bootstrap assets.

extensions/bootstrap/BootstrapAsset.php

@@ -15,7 +15,7 @@ use yii\web\AssetBundle;
  */
 class BootstrapAsset extends AssetBundle
 {
-	public $sourcePath = '@yii/bootstrap/assets';
+	public $sourcePath = '@vendor/twitter/bootstrap/dist';
 	public $css = [
 		'css/bootstrap.css',
 	];

extensions/bootstrap/BootstrapPluginAsset.php

@@ -16,7 +16,7 @@ use yii\web\AssetBundle;
  */
 class BootstrapPluginAsset extends AssetBundle
 {
-	public $sourcePath = '@yii/bootstrap/assets';
+	public $sourcePath = '@vendor/twitter/bootstrap/dist';
 	public $js = [
 		'js/bootstrap.js',
 	];

extensions/bootstrap/BootstrapThemeAsset.php

@@ -17,7 +17,7 @@ use yii\web\AssetBundle;
  */
 class BootstrapThemeAsset extends AssetBundle
 {
-	public $sourcePath = '@yii/bootstrap/assets';
+	public $sourcePath = '@vendor/twitter/bootstrap/dist';
 	public $css = [
 		'css/bootstrap-theme.css',
 	];

extensions/bootstrap/composer.json

@@ -13,7 +13,8 @@
 	},
 	"minimum-stability": "dev",
 	"require": {
-		"yiisoft/yii2": "*"
+		"yiisoft/yii2": "*",
+		"twitter/bootstrap": "3.0.*"
 	},
 	"autoload": {
 		"psr-0": { "yii\\bootstrap\\": "" }