public async Task <Household> Create(User user, Household household) { if (user.Id == null) { throw new ApplicationException("Can't create household for unstored user."); } await Households.InsertOneAsync(household); await Users.FindOneAndUpdateAsync(x => x.Id == user.Id, Builders <User> .Update.AddToSet(x => x.Households, household.Id)); Logger.LogInformation("New household created", household); return(household); }