title: How to install doctrine extensions
body: <p>While learning Symfony2 i can't find any resources that will tell me what to do to install doctrine extensions library. i know that I should add</p>
  
  <pre><code>new Stof\DoctrineExtensionsBundle\StofDoctrineExtensionsBundle(),
  </code></pre>
  
  <p>to my AppKernel.php, but what about composer? i always use it when i install eg. DoctrineFixtures, but i dont know what exactly i need to add there in this case. I tried</p>
  
  <pre><code>"gedmo/doctrine-extensions" : "master-dev",
  </code></pre>
  
  <p>But <code>php composer.phar update</code> returns php FatalError:</p>
  
  <pre><code>PHP Fatal error:  Class 'Stof\DoctrineExtensionsBundle\StofDoctrineExtensionsBundle' not found in /path/to/my/symfony/project/app/AppKernel.php on line 20
  Script Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::clearCache handling the post-update-cmd event terminated with an exception
  </code></pre>