private async void Login(string password)
        {
            if (!_connectedToDb)
            {
                return;
            }

            try
            {
                var waiter = _model.Login(password);
                if (waiter != null)
                {
                    ParametersLoader.SetParameter(AppParameters.WaiterId, waiter.Id.ToString());
                    ParametersLoader.SaveParameters();
                    await Navigation.PushAsync(App.Container.Resolve <MainPage>());

                    if (!_model.RememberUser)
                    {
                        PasswordEntry.Text = string.Empty;
                    }
                }
                else
                {
                    await DisplayAlert("Login error", "Wrong credentials, please retry", "OK");
                }
            }
            catch (WifiConnectionException ex)
            {
                await DisplayAlert("Error", ex.Message, "OK");
            }
        }
 protected override void OnDisappearing()
 {
     if (!_model.RememberUser)
     {
         ParametersLoader.SetParameter(AppParameters.Remember, _model.RememberUser.ToString());
         ParametersLoader.SaveParameters();
     }
 }