// Create or Update
        public override string PostAction(string parameters, System.Collections.Specialized.NameValueCollection querystring, string postdata)
        {
            string data = string.Empty;
            string bvin = FirstParameter(parameters);
            ApiResponse<CategoryDTO> response = new ApiResponse<CategoryDTO>();

            CategoryDTO postedCategory = null;
            try
            {
                postedCategory = MerchantTribe.Web.Json.ObjectFromJson<CategoryDTO>(postdata);
            }
            catch(Exception ex)
            {
                response.Errors.Add(new ApiError("EXCEPTION", ex.Message));
                return MerchantTribe.Web.Json.ObjectToJson(response);                
            }

            Category c = new Category();
            c.FromDto(postedCategory);

            if (bvin == string.Empty)
            {
                if (MTApp.CatalogServices.Categories.Create(c))
                {
                    bvin = c.Bvin;
                }
            }
            else
            {
                MTApp.CatalogServices.Categories.Update(c);
            }
            Category resultCategory = MTApp.CatalogServices.Categories.Find(bvin);                    
            if (resultCategory != null) response.Content = resultCategory.ToDto();
            
            data = MerchantTribe.Web.Json.ObjectToJson(response);            
            return data;
        }