App\Http\Controllers\Laralum\UsersController::addRel PHP Method

    public function addRel($user_id, $role_id)
    {
        Laralum::permissionToAccess('laralum.users.access');
        $rel = Role_User::whereUser_idAndRole_id($user_id, $role_id)->first();
        if (!$rel) {
            $rel = new Role_User();
            $rel->user_id = $user_id;
            $rel->role_id = $role_id;
            $rel->save();
        }
    }