The website is created with Middleman and deployed to Github pages.

To update the website you're going to need Ruby and bundler installed. You can read a full guide to getting started with Middleman here.

The build folder points to an orphaned git branch that goes up to Github pages on the gh-pages branch.

First off init the submodule (assuming you're in the website directory)

cd ../ && git submodule init

Next, make changes to the website in the source directory and commit these changes. Then, when you're ready to push run:

bundle exec middleman build

Change into the website/build directory push your changes:

git push origin gh-pages

Then, switch back to the website folder and commit your changes:

cd ../ && git push origin master