How to append accessories to homebridge?
I've already added homebridge to HomeKit and HomeKit recognized all my accessories. But HomeKit does not list my new added accessories which are listed in Mijia App.

I've tried restarting homebridge and clearing `cachedAccessories` but those did not work. 

What's the proper way to append accessories to homebridge?

![image](https://user-images.githubusercontent.com/1331413/51785280-48afd180-2190-11e9-85dc-a87f603b5f0b.png)
