public void Update(Author author)
 {
     db.Entry(author).State = EntityState.Modified;
     db.SaveChanges();
 }
 public void Delete(Author author)
 {
     db.Authors.Remove(author);
     db.SaveChanges();
 }
 public void Insert(Author author)
 {
     db.Authors.Add(author);
     db.SaveChanges();
 }