In #162, @ishitatsuyuki removed many "unused" packages to make our Docker images lighter and more efficient.
However, some packages identified as "unused" might actually still be necessary. Let's install them back.
[1] See the following Fluxbox error:
fbsetbg: I can't find an app to set the wallpaper with. You can install one in
many many ways but I will give you some simple advice: install Eterm and
you're set. Eterm provides Esetroot and thats a great wallpaper setter. I
recommend you install the package provided by your distro.