ensure created_by_id is being persisted correctly

(also make sure it's well tested 🎉 )

app/models.py

@@ -1007,6 +1007,9 @@ class NotificationHistory(db.Model, HistoryModel):
     phone_prefix = db.Column(db.String, nullable=True)
     rate_multiplier = db.Column(db.Float(asdecimal=False), nullable=True)
 
+    created_by = db.relationship('User')
+    created_by_id = db.Column(UUID(as_uuid=True), db.ForeignKey('users.id'), nullable=True)
+
     @classmethod
     def from_original(cls, notification):
         history = super().from_original(notification)