Change includeInJSON: Clip.idAttribute
in reverse relation to includeInJSON: Clip.prototype.idAttribute
Something like this
{
type: Backbone.HasMany
,key: 'videoCollection'
,relatedModel: Clip
,collectionType: clipCollection
,includeInJSON: Clip.prototype.idAttribute
,reverseRelation: {
key: 'parent',
includeInJSON: Clip.prototype.idAttribute
}
}