public async Task <IActionResult> SendGreeting(GreetingCreateInputModel input)
        {
            if (!this.ModelState.IsValid)
            {
                return(this.View(input));
            }

            await this.usersService.SendGreeting(input.SenderUser, input.ReceiverUser, input.Comment);

            return(this.RedirectToAction(nameof(Index)));
        }
        public IActionResult SendGreeting(string senderUsername, string receiverUsername, string phoneNumber)
        {
            var viewModel = new GreetingCreateInputModel
            {
                SenderUser   = senderUsername,
                ReceiverUser = receiverUsername,
                PhoneNumber  = phoneNumber,
            };

            return(this.View(viewModel));
        }