public async Task <ActionResult <CityAdd> > AddCityInfo([FromBody] CityAdd cityToAdd)
        {
            var duplicate = await _service.FindDuplicate(cityToAdd.Name, cityToAdd.RegionName);

            if (duplicate == null)
            {
                var cityModel = _mapper.Map <City>(cityToAdd);

                _service.AddNewCity(cityModel);
                _service.SaveChanges();

                return(Ok());
            }
            else
            {
                return(BadRequest($"{cityToAdd.RegionName} already contains {cityToAdd.Name}."));
            }
        }