part 1 of notif refactor

src/user/create.js

@@ -165,10 +165,11 @@ module.exports = function(User) {
 							bodyShort: '[[user:username_taken_workaround, ' + userData.username + ']]',
 							bodyLong: '',
 							image: 'brand:logo',
+							nid: 'username_taken:' + uid,
 							datetime: Date.now()
-						}, function(err, nid) {
-							if (!err) {
-								notifications.push(nid, uid);
+						}, function(err, notification) {
+							if (!err && notification) {
+								notifications.push(notification, uid);
 							}
 						});
 					}