public function deleteUserGroupAction($userId, $groupId)
    {
        $user = $this->getUser($userId);
        $group = $this->getGroup($groupId);

        if (!$user->hasGroup($group)) {
            return FOSRestView::create([
                'error' => sprintf('User "%s" has not group "%s"', $userId, $groupId),
            ], 400);
        }

        $user->removeGroup($group);
        $this->userManager->updateUser($user);

        return ['removed' => true];
    }