Static release build

[Libbum]

Currently, #29 & #30 are blocked since we don't have a static build of the backend. We could of course setup a VM with build tools on it, but I think in the end that's too annoying. One binary that can be thrown around is a much better idea.

But this is not that straight forward, we need a number of things to be cross compiled to musl. At least openssl for now, and libpq & libz for diesel later when we add postgres as a db option. Probably necessary for us to use sql bindings at the moment too.

The solution to this will most likely be rust-musl-builder. There is an open PR to add SQLite into the mix, so I will keep an eye on that.

[Libbum]

https://hub.docker.com/r/ekidd/rust-musl-builder/

[Libbum]

alias rust-musl-builder='docker run --rm -it -v "$(pwd)":/home/rust/src ekidd/rust-musl-builder:nightly'
rust-musl-builder cargo build --release

Is what we want, but fails due to the non-existent sqlite3 libs in the container. We'll park this for now.

[Libbum]

To move this forward we could consider moving up #25 and test with postgres.

[Libbum]

rust-musl-builder has sqllite3 in it now. We can take a look at getting this done.

update nightly with:
rust-musl-builder rustup update
doesn't seem to work. Need to fix that some other way.

[Libbum]

Functioning in 1f18b3e. I still need to figure out how to update a docker image to the latest version though to write up some docs later on. My current solution was to delete the image I had on disk and pull it from the repo again 🙅‍♂️.