private static void SeedCategories(ProductShopContext context)
        {
            using (StreamReader file = File.OpenText("../../../categories.json"))
            {
                Category[] categories = JsonConvert.DeserializeObject<Category[]>(file.ReadToEnd());

                foreach (var category in categories)
                {
                    context.Categories.AddOrUpdate(category);
                }

                context.SaveChanges();
            }
        }