fix group redirection

src/Application/Actions/Message/GroupMessagesListAction.php

@@ -19,7 +19,7 @@ class GroupMessagesListAction extends MessageAction
         if (!isset($_SESSION['userId']) || !$group->hasUser($_SESSION['userId'])){
 
             return $this->response
-            ->withHeader('Location', '/groups/')
+            ->withHeader('Location', '/groups')
             ->withStatus(302);
         }