static function getInstance()
 {
     if (self::$instance == null) {
         $obj = new Config();
         $obj->setHost($_ENV["DB_HOST"]);
         $obj->setUser($_ENV["DB_USER"]);
         $obj->setPass($_ENV["DB_PASS"]);
         $obj->setDatabase($_ENV["DB_NAME"]);
         $obj->setProvider($_ENV["DB_PROVIDER"]);
         $obj->setPort($_ENV["DB_PORT"]);
         self::$instance = $obj;
     }
     return self::$instance;
 }