Core_Command::add_site_admins PHP Method

    private static function add_site_admins($site_user)
    {
        $site_admins = array($site_user->user_login);
        $users = get_users(array('fields' => array('ID', 'user_login')));
        if ($users) {
            foreach ($users as $user) {
                if (is_super_admin($user->ID) && !in_array($user->user_login, $site_admins)) {
                    $site_admins[] = $user->user_login;
                }
            }
        }
        update_site_option('site_admins', $site_admins);
    }