Twig filter (timeago)

Added twig filter timeago for dates.

system/twig.php

@@ -19,6 +19,31 @@ if($dev_mode) {
 }
 unset($dev_mode);
 
+$filter = new Twig_SimpleFilter('timeago', function ($datetime) {
+
+	$time = time() - strtotime($datetime);
+
+	$units = array (
+		31536000 => 'year',
+		2592000 => 'month',
+		604800 => 'week',
+		86400 => 'day',
+		3600 => 'hour',
+		60 => 'minute',
+		1 => 'second'
+	);
+
+	foreach ($units as $unit => $val) {
+		if ($time < $unit) continue;
+		$numberOfUnits = floor($time / $unit);
+		return ($val == 'second')? 'a few seconds ago' :
+			(($numberOfUnits>1) ? $numberOfUnits : 'a')
+			.' '.$val.(($numberOfUnits>1) ? 's' : '').' ago';
+	}
+
+});
+$twig->addFilter($filter);
+
 $function = new TwigFunction('getStyle', function ($i) {
 	return getStyle($i);
 });