function database_add_user($username, $password, $picture, $phone)
{
    global $mysqli;
    // Sanitize the variables you passed in
    $username = sanitize_input($username);
    $password = sanitize_input($password);
    // NOTE: Add another variable to be sanitized here:
    $phone = sanitize_input($phone);
    // Hash the password so that it is not stored in the database as plain text
    $password = create_hash($password);
    // Process the picture for putting it in the database
    $picture = process_picture($picture);
    // NOTE: modify this query to also include the newfield
    // Insert the new user into the database
    $q1 = "INSERT INTO users (username, password, picture, phone)";
    $q2 = "VALUES ('{$username}','{$password}','{$picture}', '{$phone}')";
    $q = $q1 . $q2;
    $userID = 0;
    if (isUsernameTaken($username) == false) {
        // Add the user to the database
        mysqli_query($mysqli, $q);
        // Set this userID as logged in
        $userID = mysqli_insert_id($mysqli);
        set_user_logged_in($userID, $password);
    }
    return $userID;
}
switch ($cmd) {
    case 'login':
        output_header();
        form_login();
        output_footer();
        break;
    case 'process_login':
        output_header();
        process_login();
        output_footer();
        break;
    case 'publish':
        output_header();
        form_publish();
        output_footer();
        break;
    case 'create_album':
        output_header();
        create_album();
        output_footer();
        break;
    case 'add_picture':
        process_picture();
        break;
    case 'send_reg':
        send_reg_file();
        break;
    default:
        display_instructions();
}
// switch