static void AddNotBuyingFor(SecretSantaWebContext context, string buyerFirstName, string buyerFamilyName, string receiverFirstName, string receiverFamilyName)
{
var buyer = context.People.SingleOrDefault(p => p.Name == buyerFirstName && p.Family.FamilyName == buyerFamilyName);
var receiver = context.People.SingleOrDefault(p => p.Name == receiverFirstName && p.Family.FamilyName == receiverFamilyName);
buyer.NotBuyingFor = receiver;
buyer.NotBuyingForID = receiver.PersonID;
}