Change db session handling.

accountant/api/models/users.py

@@ -40,8 +40,8 @@ class User(UserMixin, db.Model):
         return self.active
 
     @classmethod
-    def query(cls, session):
-        return session.query(cls)
+    def query(cls):
+        return db.session.query(cls)
 
     @classmethod
     def hash_password(cls, password):