/**
  * Record a visit against this record by a given user, at a given IPv4 address.
  *
  * @return void
  * @author sgilbertson
  * @param array   $config Keys: user (@see User); ip (string|int).
  * */
 public function visit($config)
 {
     $user = null;
     $ip = null;
     extract($config);
     UserVisit::create_visit(array('record' => $this, 'user' => $user, 'ip' => $ip));
 }