public static function assignTerminalUser($user_id, $terminal_id)
 {
     if (TerminalUser::terminalUserExists($user_id, $terminal_id)) {
         TerminalUser::updateTerminalUserStatus($user_id, $terminal_id, 1);
     } else {
         TerminalUser::createTerminalUser($user_id, $terminal_id);
     }
 }