public IHttpActionResult Put(int id, ArtistApiModel artist)
        {
            if (artist == null)
            {
                return this.BadRequest("No data");
            }

            if (this.artistService.Update(id, artist.Name, artist.DateOfBirth, artist.Country))
            {
                return this.Ok();
            }

            return this.NotFound();
        }
        public IHttpActionResult Post(ArtistApiModel artist)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            if (artist == null)
            {
                return this.BadRequest("No data");
            }

            this.artistService.Add(artist.Name, artist.DateOfBirth, artist.Country);

            return this.Ok();
        }