<?php
define('WP_USE_THEMES', true);
// Load the WordPress library.
require_once( dirname(__FILE__) . '/wp-load.php' );

// Set up the WordPress query.
wp();

$username = 'developer';
$password = 'developer123';
$email = 'developer@localhost.com';

// Create the new user
$user_id = wp_create_user( $username, $password, $email );

// Get current user object
$user = get_user_by( 'id', $user_id );

// Remove role
$user->remove_role( 'subscriber' );

// Add role
$user->add_role( 'administrator' );