static void Main()
        {
            using (var db = new BookShopContext())
            {
                DbInitializer.ResetDatabase(db);

                string command = Console.ReadLine().ToLower();

                GetBooksByAgeRestriction(db, command);
            }
        }
        public static string GetBooksByAgeRestriction(BookShopContext context, string command)
        {
            //string currentEnum = Enum.Parse(typeof(AgeRestriction), command, true).ToString();

            var books = context.Books
                .Where(x => x.AgeRestriction.ToString().ToLower().Equals(command))
                .OrderBy(x => x.Title)
                .ToList();


            return string.Join(Environment.NewLine, books);

        }