public function actionEnable()
    {
        $maintenance = Yii::$app->maintenanceMode;

        if (!$maintenance->getIsEnabled(true) && $maintenance->enable()) {
            $this->stdout("Maintenance mode enabled successfully.\n", Console::FG_GREEN);
            return Controller::EXIT_CODE_NORMAL;
        } else {
            $this->stdout("Maintenance mode already enabled.\n", Console::FG_RED);
            return Controller::EXIT_CODE_ERROR;
        }
    }