Consider adding a `HEALTHCHECK` to docker image

[CosmicHorrorDev]

It would be nice if the Dockerfile had a HEALTHCHECK so that docker knows when the container is considered healthy. It looks like #180 takes a reasonable approach, but hasn't had any activity

[axfelix]

Hm. I'm not averse to this, and that PR looks relatively clean. Haven't used Docker's healthcheck functionality myself so am not too aware of potential downsides.

[CosmicHorrorDev]

i think the only "big" downside is that it requires pulling in curl, but that seems reasonable enough to me. i can make a fresh PR with just the healthcheck change cherry-picked if you're ok with it