public SignInCommandHandler(IAuthenticationGateway authenticationGateway,
                             ISignInPresenter signInPresenter,
                             IHashPassword hashPassword)
 {
     _authenticationGateway = authenticationGateway;
     _signInPresenter       = signInPresenter;
     _hashPassword          = hashPassword;
 }
        /// <summary>
        /// Application developers override this method to perform actions when the application starts.
        /// </summary>
        /// <remarks>
        /// To be added.
        /// </remarks>
        protected override async void OnStart()
        {
            // Handle when your app starts
            ISignInPresenter signInPresenter = App.Container.Resolve <ISignInPresenter>();

            // show the login page
            await signInPresenter.Start();
        }