public static function addVendorItem($id)
 {
     self::check_logged_in();
     $item = new Item(array('id' => $id));
     $options = array();
     $allvendoritems = VendorItem::all($options);
     $curvendoritems = $item->getVendorItems();
     function compare_vendoritems($obj_a, $obj_b)
     {
         return $obj_a->id - $obj_b->id;
     }
     $vendoritems = array_udiff($allvendoritems, $curvendoritems, 'compare_vendoritems');
     View::make('item/vendoritem/add.html', array('item_id' => $id, 'vendoritems' => $vendoritems));
 }