public static function insert($tag, $language = null)
{
$tag = (string) $tag;
$language = $language != null ? (string) $language : BL::getWorkingLanguage();
// build record
$item['language'] = $language;
$item['tag'] = $tag;
$item['number'] = 0;
$item['url'] = self::getURL($tag);
// insert and return id
return (int) BackendModel::getContainer()->get('database')->insert('tags', $item);
}