title: sonata admin one to many and many to many form
body: <p>I have OneToMany related entities Gallery and Media stored in galleries_media
  and I have Many To One related and Many To One related in GalleryMedia Entitiy</p>
  
  <pre><code>/**
  * @var ArrayCollection
  *
  * @ORM\OneToMany(targetEntity="\Entity\GalleryMedia", mappedBy="gallery", cascade={"persist", "remove"})
  */
  protected $galleriesMedia;
  </code></pre>
  
  <p>and in GalleryMedia Entitiy</p>
  
  <pre><code>/**
   * @ORM\ManyToOne(targetEntity="\Entity\Gallery", inversedBy="galleriesMedia")
   * @ORM\JoinColumn(name="gallery_id", referencedColumnName="id", nullable=false)
   */
  protected $gllary;
  
  /**
   * @ORM\ManyToOne(targetEntity="\Entity\Media", inversedBy="galleries")
   * @ORM\JoinColumn(name="media_id", referencedColumnName="id", nullable=false)
   */
  protected $media;
  </code></pre>
  
  <p>how i do this in form</p>