title: How to install the gedmo-extensions in Doctrine2?
body: <p>i'm trying to install the <a href="https://github.com/l3pp4rd/DoctrineExtensions" rel="nofollow">"gedmo" behaviourial extensions (version 2.1.0-DEV)</a> in Doctrine2 (version 2.1.3).</p>
  
  <p>Without the extensions everything works fine. However, when I add the annotationdriver to read the @gedmo-annotations errors such as "<code>Uncaught exception 'Doctrine\ORM\Mapping\MappingException' with message 'Class User2 is not a valid entity or mapped super class</code>" are thrown.
  This is de User2-entity:</p>
  
  <pre><code>&lt;?php
  
  use \Doctrine\ORM\Mapping as ORM;
  
  /** @ORM\Entity  */
  class User2 {
  
      /**
       * @ORM\Column(name="id", type="integer")
       * @ORM\Id
       * @ORM\GeneratedValue
       */
      private $id;
  
      /** @ORM\Column(length=255) */
      private $username;
  }
  </code></pre>
  
  <p>Because these errors occur even in the Entities where @gemdo is not used i suspect it has something to do with the way the annotationdrivers are configured. In my bootstrap-file the annotation driver is added (i'm only going to use the tree-extension):</p>
  
  <pre><code>$reader = new \Doctrine\Common\Annotations\AnnotationReader();
  $annotationDriver = new \Doctrine\ORM\Mapping\Driver\AnnotationDriver($reader);
  
  $chain = new \Doctrine\ORM\Mapping\Driver\DriverChain;
  $chain-&gt;addDriver($annotationDriver, 'Gedmo\Tree\Entity');
  
  $config-&gt;setMetadataDriverImpl($chain);
  </code></pre>
  
  <p>A few questions:</p>
  
  <ol>
  <li>Should I add a driver for the ORM-annotation?</li>
  <li>Is there something wrong with the User2-class?</li>
  <li>How can I get a more specific user-error enabling me to find the exact cause of the problem?</li>
  </ol>
  
  <p>In short: how can I make the @orm and @gedmo annotations work?</p>