code: function(options) {
            options = options ? _.clone(options) : {};
            if (options.parse === void 0) { options.parse = true; }
            var success = options.success;
            var collection = this;
            options.success = function(resp) {
              var arr = [];
              var keys = _.keys(resp);
              _.each(keys, function(key) {
                arr.push(resp[key]);
              });
              var method = options.reset ? 'reset' : 'set';
              collection[method](arr, options);
              if (success) { success(collection, arr, options); }
              options.autoSync = false;
              options.url = this.url;
              collection.trigger('sync', collection, arr, options);
            };
            return this.sync('read', this, options);
          }
docs: Firebase returns lists as an object with keys, where Backbone
  collections require an array. This function modifies the existing
  Backbone.Collection.fetch method by mapping the returned object from
  Firebase to an array that Backbone can use.