public ActionResult Accept(Guid businessTripId)
        {
            var businessTripModel = new BusinessTripModel(businessTripId);
            businessTripModel.ChangeStatus(BusinessTripStatus.Accepted);

            return View("StatusChangedSuccessfully");
        }
        public ActionResult Cancel(Guid businessTripId)
        {
            BusinessTripModel businessTripModel = new BusinessTripModel(businessTripId);

            if (businessTripModel.Status == BusinessTripStatus.Accepted)
            {
                Email userEmail = new Email();
                userEmail.SendCancelBusinessTripEmail(businessTripModel.Id);
            }

            businessTripModel.ChangeStatus(BusinessTripStatus.Canceled);

            return GetUserBusinessTrips();
        }