public void EditOffer(Offer offer)
        {
            OfferValidator validator = OfferValidator.CreateValidator(offer, true);

            validator.Validate();
            repository.EditOffer(offer);
        }
        public void NewOffer(Offer offer)
        {
            OfferValidator validator = OfferValidator.CreateValidator(offer, false);

            validator.Validate();
            repository.NewOffer(offer);
        }