protected static void AddLink(string link)
 {
     using (UserDBContext db = new UserDBContext())
     {
         db.Add(new Links(link));
         db.SaveChanges();
     }
 }
 public static void Register
     (string nickname, string email, string password)
 {
     using (UserDBContext db = new UserDBContext())
     {
         db.Add(new UserInfo(email, nickname, password));
         db.SaveChanges();
     }
 }