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`.