/**
 * Implements hook_user_role_insert().
 */
function {{ machine_name }}_user_role_insert($role) {
  // Save extra fields provided by the module to user roles.
  db_insert('my_module_table')
    ->fields(array(
      'rid' => $role->rid,
      'role_description' => $role->description,
    ))
    ->execute();
}