How to add nofollow attribute on adf.ly links?

I have found out how to do it. Just edit file mdc-adfly-shortener/mdc-adfly-url-shortener.php like my method below:

function adfly_url_shortcode($param){
	$url = $param['url'];
	$label_type = $param['label_type'];
	$label_text = $param['label'];
	$domain = $param['domain'];
	$ad_type = $param['ad_type'];
	$target = ($param['target'] == '_blank') ? " target='_blank'" : '';
        $rel = ($param['target'] == '_blank') ? " rel='external nofollow'" : '';
        $class = ($param['target'] == '_blank') ? " class='ext-link'" : +'+';

	if($url == '') {$url = 'https://medhabi.com';}
	if($label_type == '') {$label_type = 'long';}
	if($label_text == '') {$label_text = 'Click Here';}
	if($domain == '') {$domain = 'adf.ly';}
	if($ad_type == '') {$ad_type = 'int';}

	$adfly_url = get_adfly_url($url, $domain, $ad_type);

	if($label_type == 'long') {$label = $url;}
	elseif($label_type == 'short') {$label = $adfly_url;}
	elseif($label_type == 'text') {$label = $label_text;}

	return "<a ".$class." title = ".$label." href='".$adfly_url."'".$target."".$rel.">$label</a>";
}

$rel and $class are added.

Good job.