/**
  * Delete Tag
  *
  **/
 function delete($serial_number = '', $id = -1)
 {
     $out = array();
     $where = $id ? 'id=?' : '';
     $bindings = $id ? array($id) : array();
     $Tag = new Tag_model();
     if (!$Tag->delete_record($serial_number, $where, $bindings)) {
         $out['status'] = 'error';
     } else {
         $out['status'] = 'success';
     }
     $obj = new View();
     $obj->view('json', array('msg' => $out));
 }