public IActionResult Register([FromBody] RegisterUserViewModel viewModel)
        {
            var user = RegisterUserViewModel.FromViewModel(viewModel);

            if (_userRepository.UsernameExists(user.Username))
            {
                ModelState.AddModelError("userExists", "Ka ydoric");
                return(BadRequest(ModelState));
            }
            else
            {
                _userRepository.Add(user);
                return(Ok());
            }
        }