title: Adding a common controllers directory to a yii2 project
body: <p>I would like to add a common controller directory in my Yii2 project.</p>
  
  <p>In my <em>frontend/config/main.php</em> I have this:</p>
  
  <pre><code>'controllerNamespace' =&gt; 'frontend\controllers',
  </code></pre>
  
  <p>I would effectively like to be able to do something like this:</p>
  
  <pre><code>'controllerNamespace' =&gt; ['frontend\controllers', 'common\controllers'],
  </code></pre>
  
  <p>But this is not the correct way of doing this. It throws an <code>ArrayToStringConversionException</code>.</p>
  
  <p>I'm playing with the advanced template from the alpha release of Yii 2. Here, there's a common model directory (under common/models) and I would like to have a similar common directory for controllers and views (e.g. under common/controllers and common/views).</p>
  
  <p>Any ideas? Thanks.</p>