public function gist($link, $file=null) {
		$matches = array();
		if (preg_match('/[0-9]+/', $link, $matches)>0) {
			$gist_id = $matches[0];
			$link = "https://gist.github.com/$gist_id.js";
			if (!is_null($file)) {
				$link .= "?file=" . urlencode($file);
			}
		}

		return "<script src='$link'></script>";
	}