WordPress: admin custom user fields

wp_functions_customUserFields.php

// ----------------------------------------------------------
// ---------- Add customer user fields in wp admin ----------
// ----------------------------------------------------------
<?php
    function modify_contactmethods( $contactmethods ) {
        // Remove unwanted fields //
        unset($contactmethods['aim']);
        unset($contactmethods['yim']);
        unset($contactmethods['jabber']);
        // Add new fields //
        $contactmethods['twitter_handle'] = 'Twitter Handle (@)';
        $contactmethods['linkedin_url'] = 'LinkedIn Profile (URL)';
        return $contactmethods;
    }
    
    add_filter('user_contactmethods','modify_contactmethods');
?>