php ขอช่วยหน่อยค่ะ แก้โค้ด login user เพิ่ม admin ลงไปด้วย

<?php 
$username = $_POST['username'];
$password = $_POST['password'];

if ($username&&$password)
{

$connect = mysql_connect('localhost','root','1234') or die('Could not connect ');
mysql_select_db('phplogin')or die ('Could not find db');

$query = mysql_query ("SELECT * FROM users WHERE username='$username' ");

$numrows = mysql_num_rows($query);

if ($numrows!=0)
{

while ($row = mysql_fetch_assoc($query))
	{
		$dbusername = $row ['username'];
		$dbpassword = $row ['password'];
	}
	
	//check to see if they match!
	if ($username==$dbusername&&md5($password)==$dbpassword)
	{
	echo "welcome to website! <a href='home.php'> Click </a> here to enter the member page ";
	$_SESSION['username']=$dbusername;
	$_SESSION['sess_userid'] =  session_id() ; 

	}
	else
		echo "<script>alert('password  ไม่ถูกต้อง!!');</script>";
	
	
}
else
	die("<h3>ไม่มี username นี้ในระบบ <a href=index.html >Back </a></h3>");



}

else
	die ('<h3>กรุณาใส่ username และ  password! <a href=index.html >Back </a></h3>');



	?>