title: Cant Generate Easy-Extends of SonataUserBundle
body: <p>i am at the ending stage of installing SonataUserBundle,
  When i run,
  <code>app/console sonata:easy-extends:generate SonataUserBundle -d src --dest=src</code>
  i get </p>
  
  <blockquote>
    <p>[Doctrine\Common\Persistence\Mapping\MappingException]<br>
      Class 'Application\Sonata\UserBundle\Entity\User' does not exist </p>
  </blockquote>
  
  <p>I followed everything according to <a href="https://sonata-project.org/bundles/user/2-2/doc/reference/installation.html" rel="nofollow">This Doc</a></p>
  
  <p>Any idea how to get through it?</p>