public function getSlug($title, $allow_overlap = true)
 {
     $slug = str_slug($title);
     $slugCount = count(Tag::whereRaw("slug REGEXP '^{$slug}(-[0-9]*)?\$'")->get());
     if ($allow_overlap == false) {
         return $slugCount > 0 ? false : $slug;
     } else {
         return $slugCount > 0 ? "{$slug}-{$slugCount}" : $slug;
     }
 }