class DB {
    private static $conn;

    public static function connect() {
        if (!self::$conn) {
            $cfg = require __DIR__.'/../config/database.php';
            self::$conn = new PDO(
              "mysql:host={$cfg['host']};dbname={$cfg['db']}",
              $cfg['user'],
              $cfg['pass'],
              [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
            );
        }
        return self::$conn;
    }
}