Allow apps to register plugins for the user management

Signed-off-by: Joas Schilling <coding@schilljs.com>

settings/js/users/users.js

@@ -677,6 +677,7 @@ var UserList = {
 };
 
 $(document).ready(function () {
+	OC.Plugins.attach('OC.Settings.UserList', UserList);
 	$userList = $('#userlist');
 	$userListBody = $userList.find('tbody');
 	$userListHead = $userList.find('thead');