title: Display ManyToOne as Selectbox
body: <p>I'm using <code>AnnotationForms</code> and created a valid <code>Doctrine</code> ManyToOne relationship. I checked it in the database - its working.</p>
  
  <p>The foreign key field is just displayed as an input field. Is there a way to automatically let the framework create a <code>Selectbox</code> which is filled with Objects of the related Entity?</p>