/**
  * Lista los permisos de un determinado usuario.
  *
  * @param  int  $id
  * @return Response
  */
 public function permissions($id)
 {
     $data["id"] = $id;
     $validator = Validator::make($data, ['id' => 'integer']);
     if ($validator->fails()) {
         return response()->json(["msg" => "alert", "validator" => $validator->messages()], 200);
     }
     if ($role = Role::find($id)) {
         $role_user = Role_user::leftjoin('users', 'role_user.user_id', '=', 'users.id')->leftjoin('permission_role', 'permission_role.role_id', '=', 'role_user.role_id')->leftjoin('permissions', 'permissions.id', '=', 'permission_role.permission_id')->where('user_id', $id)->get(['name', 'username', 'email']);
         if ($role_user and current(current($role_user))) {
             return response()->json(["msg" => "Success", "users" => $role_user], 200);
         } else {
             $description = "Usuario sin permisos";
         }
     } else {
         $description = "No se ha encontrado el usuario";
     }
     return response()->json(["msg" => "error", "description" => $description], 200);
 }