// Related Post
function get_related_posts($post_id, $tags = array()) {
	$query = new WP_Query();
	
	$post_types = get_post_types();
	unset($post_types['page'], $post_types['attachment'], $post_types['revision'], $post_types['nav_menu_item']);
	
	if($tags) {
		foreach($tags as $tag) {
			$tagsA[] = $tag->term_id;
		}
	}
	$query = new WP_Query( array('showposts' => 4,'post_type' => $post_types,'post__not_in' => array($post_id),'tag__in' => $tagsA,'ignore_sticky_posts' => 1,
	));
  	return $query;
}