title: Knplabs translatable: How to find an entry by a translatable field?
body: <p>I have an entity with the Knp Doctrine behaviors Translatable and Sluggable. Everything works fine so when I create or update an entry there is a slug for each language generated from the title.</p>
  
  <p>The question ist how can i find an entry by a translated slug?</p>
  
  <p>This will throw an error "has no field 'slug'":</p>
  
  <pre><code>$this-&gt;getDoctrine()-&gt;getRepository('AcmeTestBundle:News')-&gt;findOneBySlug($slug);
  </code></pre>