code: public static function categoriesMenu($categories)
      {
          $menu = '<ul class="nav nav-pills nav-stacked">';
  
          foreach ($categories as $category) {
              $menu .= '<li>';
              $menu .= '<a href="/'.config('chatter.routes.home').'/'.config('chatter.routes.category').'/'.$category['slug'].'">';
              $menu .= '<div class="chatter-box" style="background-color:'.$category['color'].'"></div>';
              $menu .= $category['name'].'</a>';
  
              if (count($category['parents'])) {
                  $menu .= static::categoriesMenu($category['parents']);
              }
  
              $menu .= '</li>';
          }
  
          $menu .= '</ul>';
  
          return $menu;
      }
docs: This function construct the categories menu with nested categories.
  
  @param array $categories
  
  @return string