assets/js/vendor/backbone-relational.js
function( collection ) {
			if ( this.related ) {
				this.stopListening( this.related );
			}

			if ( !collection || !( collection instanceof Backbone.Collection ) ) {
				var options = _.isFunction( this.options.collectionOptions ) ?
					this.options.collectionOptions( this.instance ) : this.options.collectionOptions;

				collection = new this.collectionType( null, options );
			}

			collection.model = this.relatedModel;

			if ( this.options.collectionKey ) {
				var key = this.options.collectionKey === true ? this.options.reverseRelation.key : this.options.collectionKey;

				if ( collection[ key ] && collection[ key ] !== this.instance ) {
					if ( Backbone.Relational.showWarnings && typeof console !== 'undefined' ) {
						console.warn( 'Relation=%o; collectionKey=%s already exists on collection=%o', this, key, this.options.collectionKey );
					}
				}
				else if ( key ) {
					collection[ key ] = this.instance;
				}
			}

			this.listenTo( collection, 'relational:add', this.handleAddition )
				.listenTo( collection, 'relational:remove', this.handleRemoval )
				.listenTo( collection, 'relational:reset', this.handleReset );

			return collection;
		}
function( collection ) {
			if ( this.related ) {
				this.stopListening( this.related );
			}

			if ( !collection || !( collection instanceof Backbone.Collection ) ) {
				var options = _.isFunction( this.options.collectionOptions ) ?
					this.options.collectionOptions( this.instance ) : this.options.collectionOptions;

				collection = new this.collectionType( null, options );
			}

			collection.model = this.relatedModel;

			if ( this.options.collectionKey ) {
				var key = this.options.collectionKey === true ? this.options.reverseRelation.key : this.options.collectionKey;

				if ( collection[ key ] && collection[ key ] !== this.instance ) {
					if ( Backbone.Relational.showWarnings && typeof console !== 'undefined' ) {
						console.warn( 'Relation=%o; collectionKey=%s already exists on collection=%o', this, key, this.options.collectionKey );
					}
				}
				else if ( key ) {
					collection[ key ] = this.instance;
				}
			}

			this.listenTo( collection, 'relational:add', this.handleAddition )
				.listenTo( collection, 'relational:remove', this.handleRemoval )
				.listenTo( collection, 'relational:reset', this.handleReset );

			return collection;
		}
Bind events and setup collectionKeys for a collection that is to be used as the backing store for a HasMany.
If no 'collection' is supplied, a new collection will be created of the specified 'collectionType' option.
@param {Backbone.Collection} [collection]
@return {Backbone.Collection}