direnv (https://direnv.net/) development environment for local development of
a GitHub-Pages site. This is a more complex alternative to nix-shell -p jekyll
which should work fine in most cases but which is not guaranteed to exactly
match the GitHub-Pages environment.
For more information, see:
https://discourse.nixos.org/t/shell-nix-for-github-pages-development/2000
direnv allow
make # or "bundle install"
Then run make serve or jekyll serve. Run make update or bundle update to
update to the latest version of the github-pages gem.
bundle install will fail when the directory path contains spaces.