Add relationships to client models

No issue
- Removed tabs from tag.js (why didn't jshint catch this?)
- Removed superfluous `activate` in SettingsIndexRoute
- updated `UserModel` and `TagModel` to have `created_by, updated_by` be references to `user` objects.
- updated `UserModel` to use `moment-date` instead of `date`

ghost/admin/models/tag.js

@@ -6,10 +6,10 @@ var Tag = DS.Model.extend({
     parent_id: DS.attr('number'),
     meta_title: DS.attr('string'),
     meta_description: DS.attr('string'),
-	created_at: DS.attr('date'),
-	created_by: DS.attr('number'),
-	updated_at: DS.attr('date'),
-	updated_by: DS.attr('number')
+    created_at: DS.attr('moment-date'),
+    created_by: DS.belongsTo('user', {async: true}),
+    updated_at: DS.attr('moment-date'),
+    updated_by: DS.belongsTo('user', {async: true})
 });
 
 export default Tag;

ghost/admin/models/user.js

@@ -20,9 +20,9 @@ var User = DS.Model.extend(NProgressSaveMixin, ValidationEngine, {
     meta_description: DS.attr('string'),
     last_login: DS.attr('moment-date'),
     created_at: DS.attr('moment-date'),
-    created_by: DS.attr('number'),
+    created_by: DS.belongsTo('user', { async: true }),
     updated_at: DS.attr('moment-date'),
-    updated_by: DS.attr('number'),
+    updated_by: DS.belongsTo('user', { async: true }),
 
     saveNewPassword: function () {
         var url = this.get('ghostPaths.url').api('users', 'password');

ghost/admin/routes/settings/index.js

@@ -1,9 +1,6 @@
 import {mobileQuery} from 'ghost/utils/mobile';
 
 var SettingsIndexRoute = Ember.Route.extend(Ember.SimpleAuth.AuthenticatedRouteMixin, {
-    activate: function () {
-        this._super();
-    },
     // redirect to general tab, unless on a mobile phone
     beforeModel: function () {
         if (!mobileQuery.matches) {