title: Fatal error: Class 'AppBundle\AppBundle' not found in AppKernel.php after install DoctrineFixturesBundle
body: <p>I try install DoctrineFixturesBundle in symfony 2.6.6 using this <a href="http://symfony.com/doc/current/bundles/DoctrineFixturesBundle/index.html" rel="nofollow">documentation</a>. However, I get:</p>
  
  <blockquote>
    <p>Fatal error: Class 'AppBundle\AppBundle' not found</p>
  </blockquote>
  
  <p>If I remove <code>AppBundle\AppBundle</code> from <code>AppKernel.php</code>, I have the same problem with another bundle. I installed Symfony via the Symfony installer and my <code>composer.json</code> was empty before I added:</p>
  
  <pre><code>{
      "require": {
          "doctrine/doctrine-fixtures-bundle": "2.2.*"
      }
  }
  </code></pre>
  
  <p>Maybe this is a part of the problem?</p>