private async Task<VendingSnack> StoreAsync(VendingSnack snack)
        {
            List<VendingSnack> snacks = new List<VendingSnack>(); 
            foreach(VendingSnack s in db.VendingSnacks)
            {
                snacks.Add(s);
            }

            var selectedSnack = await db.VendingSnacks.FindAsync(snack.Id+1);
            selectedSnack.Purchased = true;
            return await db.VendingSnacks.FirstOrDefaultAsync(x => x.Purchased != true && x.SlotId == selectedSnack.SlotId);
        }
        public async Task<IHttpActionResult> Post(VendingSnack snack)
        {
            if (!ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var nextSnack = await this.StoreAsync(snack);
            return this.Ok<VendingSnack>(nextSnack);
        }