public async Task Create(CreatePosterInput input)
        {
            Poster output = input.MapTo <Poster>();
            //await _authorManager.Create(output);
            var poster = _posterRepository.FirstOrDefault(x => x.Id == output.Id);

            if (poster != null)
            {
                throw new UserFriendlyException("Already Exist");
            }
            else
            {
                await _posterRepository.InsertAsync(output);
            }
        }
        public void Update(UpdatePosterInput input)
        {
            Poster output = input.MapTo <Poster>();

            _posterRepository.Update(output);
        }