// POST api/Artists
        public HttpResponseMessage PostArtist(ArtistModel artist)
        {
            if (artist == null)
            {
                var errResponse = Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Error!");
                return errResponse;
            }

            Artist artistToAdd = artist.ToArtist();
            var entity = this.repository.Add(artistToAdd);

            var response = this.Request.CreateResponse(HttpStatusCode.Created, entity);
            response.Headers.Location =
                new Uri(this.Request.RequestUri + artist.ArtistId.ToString(CultureInfo.InvariantCulture));
            return response;
        }