/**
* create new task
* @param string $keyword keyword to search for
* @return none
*/
public function task($keyword)
{
parent::__construct($keyword, 2);
$total = $this->total();
$this->_db->query("insert into `task` (`keyword`,`total`) values ('{$keyword}',{$total})");
// TODO 这里自动创建数据表
parent::__destruct();
// free memory
}