Update error unhandled rejection Error
Hi,
**When i click the Update button on the Hombridge UI i always get this error:**
![hombridgeuierror](https://user-images.githubusercontent.com/9810157/55291828-bc19cd80-53e3-11e9-90be-f020a317ca6f.png)

**in the synology docker-terminal:**
![dockererror](https://user-images.githubusercontent.com/9810157/55291823-b15f3880-53e3-11e9-9e9f-32983913c6a4.PNG)

what did i wrong?
