creating notification file under events directo

packages/app/src/server/events/notification.ts

@@ -0,0 +1,17 @@
+const debug = require('debug')('growi:events:page');
+const util = require('util');
+const events = require('events');
+
+function NotificationEvent(crowi) {
+  this.crowi = crowi;
+
+  events.EventEmitter.call(this);
+}
+util.inherits(NotificationEvent, events.EventEmitter);
+
+NotificationEvent.prototype.onUpdate = function(page, user) {
+  debug('onUpdate event fired');
+};
+
+
+module.exports = NotificationEvent;