title: Yii2 - app assets
body: <p>Yii is great but assets is the thing that was always strange for me (since the 1.1 version).
  I'm using Yii2 currently with Advanced app template. I want to register some css/js files in frontend <code>main</code> layout view (trying to use <a href="http://html5up.net/prologue" rel="nofollow">HTML5UP Prologue Template</a>).
  How it can be done? I placed my <code>css</code> files under <code>frontend/web/css</code> directory, <code>js</code> under <code>frontend/web/js</code> and layout images under <code>frontend/web/images</code> dir. </p>
  
  <p>Under <code>frontend/assets</code> directory I created <code>PrologueAssets</code> class like this:</p>
  
  <pre><code>namespace frontend\assets;
  use yii\web\AssetBundle;
  
  class PrologueAssets extends AssetBundle {
  
      public $sourcePath = "@webroot";
      public $css = [
          'css/skel.css',
          'css/style.css',
          'css/style-wide.css',
      ];
      public $js = [
          'js/jquery.min.js',
          'js/jquery.scrolly.min.js',
          'js/jquery.scrollzer.min.js',
          'js/skel.min.js',
          'js/skel-layers.min.js',
          'js/init.js',
      ];
  
      static function register($view) {
          die(self::sourcePath);
          parent::register($view);
      }
  
  }
  </code></pre>
  
  <p>Unfortunately none of these files are registered. How to do that?</p>
  
  <p>Little second question - how to register css files only if eg IE8 or IE9 is detected?</p>