function addToGuestbook()
{
  if(!(isset($_POST['autor']) && ($autor = $_POST['autor']) &&
     isset($_POST['tresc']) && ($tresc = $_POST['tresc']))){
    $this->setMessage("Prosz poda poprawne dane.");
    return ACTION_FAILED;
  }
  
  //tu mona wykona dodatkow weryfikacj poprawnoci danych
  
  $query  = "INSERT INTO guestbook (autor,tresc) ";
  $query .= "VALUES (:autor, :tresc)";
  
  if(!(($stm = $this->dbo->prepare($query)) && 
     ($stm->execute(array('autor'=>$autor, 'tresc'=>$tresc))))){
    $this->setMessage("Wystpi bd serwera.");
    return ACTION_FAILED;
  }
  $this->setMessage("Wpis zosta dodany do ksigi goci.");
  return ACTION_OK;
}