add HA Addon link

[OttPeterR]

Hey, I love using baby buddy so I put this together. Currently only <your_ip:port> access works -- the ingress doesn't at the moment so maybe we could collaborate and figure that out at some point!

[coveralls]

Coverage decreased (-0.05%) to 98.099% when pulling d7c1651 on OttPeterR:master into 5964eed on babybuddy:master.

[cdubz]

Thanks for adding! I'd be happy to try to help with the integration where I can. I was also just looking at #374 with a user that may be related. I'm not at all familiar with HA though. Is there a good guide for getting a test environment up quickly?

[OttPeterR]

Here's the guide for addons: https://developers.home-assistant.io/docs/add-ons

From a high level, HA addons are docker containers that open a port for their UI, HA then makes that UI accessible through the HA UI, this lets a bunch of services get funneled through a single URL with added security. The issue I'm having is changing the base URL of baby buddy, because each HA addon needs its own unique url extension. This looks like it maybe be similar to what #186 was having. But the common solution for other addons is to rewrite requests with nginx - and that's where I'm having issues. I know almost nothing about nginx so I'm fumbling around trying to get it to work.

Let's take this discussion off this PR so it can be done with, but I'll sure appreciate any help I can get!