public function register_settings()
{
register_setting('bbsub_options', 'bbsub_topic_notification', array(__CLASS__, 'validate_topic_notification'));
add_settings_section('bbsub_options_bbpress', 'bbPress', '__return_null', 'bbsub_options');
add_settings_field('bbsub_options_bbpress_topic_notification', 'New Topic Notification', array(__CLASS__, 'settings_field_topic_notification'), 'bbsub_options', 'bbsub_options_bbpress');
}