public async Task <IActionResult> Create([FromBody] AppointmentViewModel viewModel)
        {
            var command = new CreateAppointmentCommand(viewModel);
            var result  = await mediator.Send(command);

            var locationUri = uriService.GetAppointmentUri(ApiRoutes.Appointments.Get, result.AppointmentId.ToString());

            return(CreatedAtAction("locationUri", result));
        }