Should document how the SETUPFILE should be setup in the source

[olberger]

In the provided source file, the SETUPFILE is pointing to an absolute file:

#+SETUPFILE: ~/org/theme-readtheorg.setup

which isn't provided in the current repo.

But I guess it should correspond to the one provided in the other repo from the author: https://github.com/fniessen/org-html-themes/blob/master/org/theme-readtheorg.setup

Assuming someone git-cloned both repos in close subdirs, it may be changed to:

#+SETUPFILE: ../org-html-themes/org/theme-readtheorg.setup

whch will provide a much smoother UX :-)

Hth