title: FOS UserBundle Unable to login
body: <p>I'm back with another issue regarding my UserBundle :
  Everything went perfect while installing and configuring FOS bundle through Symfony2, it even let me create 2 users that were properly inserted into my DB.</p>
  
  <p>However, every time I try to login into either of these accounts, I get the following error</p>
  
  <pre><code>Warning: Erroneous data format for unserializing 'VillaPrivee\UserBundle\Entity\User' in /Users/Vianney/Projets/VillaPrivee/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/ClassMetadataInfo.php line 869
  </code></pre>
  
  <p>This is what the line 869 refers to :</p>
  
  <pre><code>/**
       * Creates a new instance of the mapped class, without invoking the constructor.
       *
       * @return object
       */
      public function newInstance()
      {
          if ($this-&gt;_prototype === null) {
              $this-&gt;_prototype = unserialize(sprintf('O:%d:"%s":0:{}', strlen($this-&gt;name), $this-&gt;name));
          }
  
          return clone $this-&gt;_prototype;
      }
  </code></pre>
  
  <p>And this is my User entity :</p>
  
  <pre><code>namespace VillaPrivee\UserBundle\Entity;
  
  use FOS\UserBundle\Model\User as BaseUser;
  use Doctrine\ORM\Mapping as ORM;
  
  /**
   * @ORM\Entity
   * @ORM\Table(name="fos_user")
   */
  class User extends BaseUser
  {
      /**
       * @ORM\Id
       * @ORM\Column(type="integer")
       * @ORM\GeneratedValue(strategy="AUTO")
       */
      protected $id;
  
      public function __construct()
      {
          parent::__construct();
          // your own logic
      }
  }
  </code></pre>
  
  <p>Not sure what I did wrong, since I just installed the whole thing following the step by step documentation...
  Thanks guys for your help</p>