<?php
if ( ! isset( $wp_roles ) ) {
	$wp_roles = new WP_Roles();
}

  $iclsettings                           = get_option( 'icl_sitepress_settings' );
  $iclsettings['st']['translated-users'] = array_keys( $wp_roles->roles );
  update_option( 'icl_sitepress_settings', $iclsettings );