public void WriteToFile(string path, IRepository saver)
 {
     if (saver == null)
         saver = new FileStorage();
     saver.SaveTo(path, bookList);
 }
 public void ReadFromFile(string path, IRepository saver)
 {
     if (saver == null)
         saver = new FileStorage();
     bookList = saver.ReadFrom(path);
 }