Advanced Usage?

Hey, I'm wondering if there is any appetite for advanced usage.

I really want the hostname for my host to be on the lock screen. I do it like so:

```
HOSTNAME=$(hostname -f) FONT_FAMILY=$(fc-list : family file | grep google-fonts/DISPLAY | cut -d " " -f 2- | cut -d , -f 1 | shuf -n1) envsubst < dracula-wallpaper.svg.envsubst_tpl >! dracula-wallpaper.svg
```

where I've added

```
${HOSTNAME}
```

to the bottom of the SVG and renamed it to svg.envsubt_tpl.

I'm not sure if there is as easy a way of doing this in this repo, except through documentation, but it may help someone else who ends up here.

(I installed google fonts according to my note here on this gist: https://gist.github.com/iacchus/5f694e726e80e4b9141f5ee082bfe848?permalink_comment_id=4621031#gistcomment-4621031)

It could be a better color also....