public function kirjaudu($tunnus, $passu) {
        $sql = "SELECT * FROM users WHERE username = :tunnus AND password = :passu LIMIT 1;";
        $stmt = $this->yhteys->prepare($sql, array(PDO::FETCH_ASSOC));

        /*
        $stmt->bindParam(":tunnus", $tunnus);
        $stmt->bindParam(":passu", $passu);
        $stmt->execute();
        */
        $stmt->execute(array(":tunnus" => $tunnus, ":passu" => $passu));


        $result = $stmt->fetch();
        if ($stmt->rowCount() == 1) {
            $this->tila = 1;
            // Jos k�ytt�j� l�ytyy ja passu t�sm��, lis�t��n se adminiin, jotta h�n voi hallita viestej�
            if ($result["role"] == "admin") {
                $_SESSION["role"] = "admin";
                //$_SESSION["admin"] = $result["username"];
            } else {
                $_SESSION["role"] = user;
                //$_SESSION["user"] = $result["username"];
            }
            $_SESSION["username"] = $result["username"];
            //$kayttaja = $_SESSION["username"];
            //$kayttaja = $result;
            header("location: index.php");

        } else {
            return false;
        }
    }