How can I use this with a xxx.ghe.com domain?

[derkoe]

Can't find any configuration option for a base URL. Is this even possible?

[karpikpl]

I think that should work - I created #364, feel free to review. According to my research APIs should work.
You could check if you're getting data via GH API calls, just to confirm

[karpikpl]

@derkoe I merged support for custom base URL