Untitled

<html>
    <body>
        <h1>User Creature</h1>
        <?php
        session_start();
        if($_SESSION['login'] !="OK")
        {
            header('Location: login.php');
            exit();
        }
        $servername="localhost";
        $db_user="DATABASE_USERNAME";
        $db_password="DATABASE_PASSWORD";
        $db_name="DATABASE_NAME";

        $new_user=$_POST["new_username"];
        $new_pass=$_POST["new_password"];
        // Create connection
        $conn = new mysqli($servername, $db_user, $db_password, $db_name);
        // Check connection
        if ($conn->connect_error)
        {
            die("Connection failed;".$conn->connect_error);
        }
        $sql="INSERT INTO 'users'('userID', 'username', 'password')
        VALUES (NULL, '$new_user', '$new_pass')";

        $result=mysqli_query($conn,$sql);
        echo"<p>User create successfully.</p>";
        echo"<p>Return to <a href='protected.php'>application</a>
        or<a href='login.php'>log out</a></p>";
        ?>
    </body>
</html>