fix(aurora): make sure the user_id in changes is always an integer

aurora/models.py

@@ -301,7 +301,8 @@ class Change(AuroraBaseModel):
         data.update({
             "timestamp": timestamp,
             "end_timestamp": end_timestamp,
-            "duration": duration
+            "duration": duration,
+            "user_id": int(data["user_id"])
         })
         return cls(bot=bot, **data)