$q = 'SELECT * FROM users WHERE username=:username AND password=:password';
    $q2 = 'UPDATE users SET modication_time=NOW() WHERE username=:username AND password=:password';
    $query = $dbh->prepare($q);
    $query->execute(array(':username' => $username, ':password' => $pwd));
    $query2 = $dbh->prepare($q2);
    $query2->execute(array(':username' => $username, ':password' => $pwd));
	if($query->rowCount() == 0){
		header('Location: index.php?err=1');
	}else{
		$row = $query->fetch(PDO::FETCH_ASSOC);

		session_regenerate_id();