@Override
 public boolean signIn(String email, String password) {
   if (email == null || email.isEmpty()) return false;
   User user = userController.getByEmail(email);
   if (user != null && SecurityUtil.hashPassword(password).equals(user.getPassword())) {
     CurrentUser.set(user);
     ConnectedUsers.INSTANCE.addUser(user);
     return true;
   }
   return false;
 }
 @Override
 public String getPrincipalName() {
   return CurrentUser.get().getName();
 }
 @Override
 public boolean isUserSignedIn() {
   return !(CurrentUser.get() == null);
 }