// structure for media objects.
// for images
{ id, caption, src, RelatedMedia : [_id1, _id2, . . ] }

// for videos
{ id, title, youtubeScript, RelatedMedia : [_id1, _id2, . . ]  }

// for documents/Articles
{ id, name, article, RelatedMedia : [_id1, _id2, . . ]  }