Today I learned how to use git modules:

First you add the submodule reference to .gitconfig & .gitmodules:

$ git submodule add <remote_url> <destination_folder>

Then pull the submodule when it updates:

$ git submodule update --remote --merge

Incidentally, I am now using this method to make codegard1/blackjack a submodule of this site’s repo. Consequently, I don’t have to manually copy over the source code for blackjack to include it on this site anymore.