Emit signal on active change about fcm-django

[xtrinch]

Well the question at hand is how much worse will the performance be, if you call save on individual models so that the post_save handler would be triggered.

What is the use case of using post_save? Is it anything that could be handled differently?

[Andrew-Chen-Wang]

I think adding a signal for something scalable like notifications would be potentially harmful. Over at djangorestframework-simplejwt, I considered the same problem and came to the conclusion that we could add a setting saying whether we wanted to emit a signal. I don't think a signal will be necessary though. On the one hand, if a device is being deactivated, you can receive the ids from the QuerySet API response (from #160). From DRF, override some views. And from admins, override the ModelAdmin class