function validate_user($username = "", $password = "")
    {
        $password = md5($password);

        $user_test = $this->CI->db->get_where('users', array('username'=>$username, 'password'=>$password));

        if ($user_test->num_rows() == 0)
        {
            return FALSE;
        }

        else
        {
            $result = $user_test->row();
            return $result->id;
        }
    }