Problem: The Docker example was using Alpine with the Tini dependency
and some neat custom stuff, but it wasn't super clear to understand
everything that was going on. It was also slow because lots of stuff was
compiling from source.
Solution: Replace neat custom stuff with boring defaults for clarity and
much faster builds.
Previously you would get this error due to imperfect path creation
```
node contrib/install-systemd-service.js
fs.js:114
throw err;
^
Error: ENOENT: no such file or directory, copyfile '/home/justin/src/github.com/fraction/oasis/contrib/oasis.service' -> '/home/justin/.config/systemd/user/oasis.service'
at Object.copyFileSync (fs.js:1728:3)
at Object.<anonymous> (/home/justin/src/github.com/fraction/oasis/contrib/install-systemd-service.js:27:6)
at Module._compile (internal/modules/cjs/loader.js:778:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:831:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
```
I was having a problem where I'd start my computer but the script wasn't
restarting audomatically, and after some searching I found this:
https://github.com/systemd/systemd/issues/2690#issuecomment-186973730
It looks like we should be using `default.target` instead of
`multi-user.target`.