private async void AddPlayerButton_Click(object sender, RoutedEventArgs e)
        {
            var player = new Player
            {
                Name = AddPlayerTextBox.Text
            };

            await viewModel.AddPlayerAsync(player);
        }
        public async Task AddPlayerAsync(Player player)
        {
            IsPending = true;
            ErrorMessage = null;

            try
            {
                IMobileServiceTable<Player> table = _client.GetTable<Player>();
                await table.InsertAsync(player);
                Players.Add(player);
            }
            catch (MobileServiceInvalidOperationException ex)
            {
                ErrorMessage = ex.Message;
            }
            catch (HttpRequestException ex2)
            {
                ErrorMessage = ex2.Message;
            }
            finally
            {
                IsPending = false;
            }
        }
        public async Task SubmitScoreAsync(Player player, int score)
        {
            IsPending = true;
            ErrorMessage = null;

            var playerScore = new PlayerScore()
            {
                PlayerId = player.Id,
                Score = score
            };

            try
            {
                await _client.InvokeApiAsync<PlayerScore, object>("score", playerScore);
                await GetAllRanksAsync();
            }
            catch (MobileServiceInvalidOperationException ex)
            {
                ErrorMessage = ex.Message;
            }
            catch (HttpRequestException ex2)
            {
                ErrorMessage = ex2.Message;
            }
            finally
            {
                IsPending = false;
            }
        }