[backbone] Add model, template and view for group navigation popup

media/scripts/app/models/group.js

@@ -0,0 +1,10 @@
+define([
+    'underscore',
+    'backbone'
+], function(_, Backbone) {
+    'use strict';
+
+    var Group = Backbone.Model.extend({});
+
+    return Group;
+});