Remove unused imports

flaskbb/user/models.py

@@ -11,10 +11,8 @@
 import os
 from datetime import datetime, timedelta
 
-from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
-from itsdangerous import SignatureExpired
 from werkzeug.security import generate_password_hash, check_password_hash
-from flask import current_app, url_for
+from flask import url_for
 from flask_login import UserMixin, AnonymousUserMixin
 
 from flaskbb._compat import max_integer