/**
  * get the ip of the user and set it to a defined column
  *
  * @param string  $str name of the column.
  *
  * @access public
  *
  * @return mixed Value.
  */
 public function addIP($str = 'user_ip')
 {
     $this->add($str, Extras::getIp());
     return $this;
 }