public async Task<Expense> Save(string description, double cost, IEnumerable<User> splitees)
        {
            Expense expense = new Expense();
            expense.Cost = cost.ToString();
            expense.Description = description;
            expense.Users = new List<Payment>();

            // Add your friends to the payment
            foreach (User user in splitees)
            {
                Payment payment = new Payment();

                payment.OwedShare = Math.Round((cost / (splitees.Count() + 1)), 2).ToString(); // Split the cost evenly (+1 because we need to count the current user)
                payment.PaidShare = "0.0";
                payment.User = user;

                expense.Users.Add(payment);
            }

            // Add you
            double remainingShare = cost - expense.Users.Select(payment => double.Parse(payment.OwedShare)).Aggregate((sum, next) => sum + next);
            expense.Users.Add(new Payment() { OwedShare = remainingShare.ToString(), PaidShare = expense.Cost, User = proxy.CurrentUser });

            Expense savedExpense = await proxy.CreateExpense(expense);

            return savedExpense;
        }
        public async Task<Expense> CreateExpense(Expense expense)
        {
            var request = new RestRequest("create_expense", Method.POST);

            JObject payload = new JObject();
            payload["cost"] = expense.Cost;
            payload["payment"] = false;
            payload["description"] = expense.Description;

            for (int i = 0; i < expense.Users.Count; i++)
            {
                Payment payment = expense.Users[i];
                payload.AddIfNotDefault("users__" + i + "__user_id", payment.User.Id);
                payload.AddIfNotDefault("users__" + i + "__fist_name", payment.User.FirstName);
                payload.AddIfNotDefault("users__" + i + "__last_name", payment.User.LastName);
                payload.AddIfNotDefault("users__" + i + "__email", payment.User.Email);
                payload.AddIfNotDefault("users__" + i + "__paid_share", payment.PaidShare);
                payload.AddIfNotDefault("users__" + i + "__owed_share", payment.OwedShare);
            }
 
            var str = payload.ToString();
            request.AddParameter("application/json", str, ParameterType.RequestBody);

            ExpenseWrapper result = await this.client.ExecuteRequestAsync<ExpenseWrapper>(request);
            if (result.Expenses.Count == 1)
            {
                // Success
                return result.Expenses[0];
            } 

            return null;
        }