createModels = function() {
						// Find (or create) a model for each one that is to be fetched
						models = _.map( idsToFetch, _.bind(function( id ) {
							var model = rel.relatedModel.findModel( id );

							if ( !model ) {
								var attrs = {};
								attrs[ rel.relatedModel.prototype.idAttribute ] = id;
								model = rel.relatedModel.findOrCreate( attrs, options );
								createdModels.push( model );
							}

							return model;
						}, this) );
					}
Get related objects. Returns a single promise, which can either resolve immediately (if the related model[s])
are already present locally, or after fetching the contents of the requested attribute.
@param {string} attr The relation key to fetch models for.
@param {Object} [options] Options for 'Backbone.Model.fetch' and 'Backbone.sync'.
@param {Boolean} [options.refresh=false] Fetch existing models from the server as well (in order to update them).
@return {jQuery.Deferred} A jQuery promise object. When resolved, its `done` callback will be called with
 contents of `attr`.