public static void addRezervation(string username, string hotelName)
{
utils.DbUtils dbUtil = new utils.DbUtils();
int id = dbUtil.getIdOfHotel(hotelName);
dbUtil.addRezervationHotel(id, username);
dbUtil.decreaseSeatsHotel(id);
HttpContext.Current.Session["hotel"] = hotelName;
}