move route to create a group

app/routes.php

@@ -125,6 +125,7 @@ return function (App $app) {
                 return $this->get(Twig::class)->render($response, "/group/create_group.twig", []);
                 });
             $group->get('', ListGroupsAction::class);
+            $group->post('', CreateGroupAction::class);
             $group->post('/{id}/delete', DeleteGroupAction::class);
             $group->get('/{id}/modify', ViewModifyGroupForm::class);
             $group->post('/{id}/modify', ModifyGroupAction::class);