title: how can I use custom extenstion/widget in yii2?
body: <p>I use gii to generate a extension in yii2.0, here is the code</p>
  
  <p>namespace ms\editor;</p>
  
  <pre><code>/**
   * This is just an example.
   */
  class AutoloadExample extends \yii\base\Widget
  {
      public function run()
      {
          return "Hello!";
      }
  }
  </code></pre>
  
  <p>when I want to use it in my view file,</p>
  
  <pre><code>use ms\editor\AutoloadExample;
  ...
  &lt;?= AutoloadExample::widget();?&gt;
  </code></pre>
  
  <p>I use yii2 baisic template, and I put the "ms" folder in "vendor" folder, but it just tell me class ms\editor\AutoloadExample not found, what should I to make yii2 to find the class?is there something like "components"or "extension" folder in yii1.1?
  can you help me? </p>