code: function(model) {
            var remoteAttributes;
            var localAttributes;
            var updateAttributes;
            var ref;
  
            // if the model is already being handled by listeners then return
            if (model._remoteChanging) {
              return;
            }
  
            remoteAttributes = model._remoteAttributes || {};
            localAttributes = model.toJSON();
  
            // consolidate the updates to Firebase
            updateAttributes = this._compareAttributes(remoteAttributes, localAttributes);
  
            ref = this.firebase.ref().child(model.id);
  
            // if '.priority' is present setWithPriority
            // else do a regular update
            if (_.has(updateAttributes, '.priority')) {
              this._setWithPriority(ref, localAttributes);
            } else {
              this._updateToFirebase(ref, localAttributes);
            }
  
          }
docs: Add handlers for all models in this collection, and any future ones that may be added.