First, you need to have Ruby and Gem installed, which may look like this:
sudo apt-get install ruby ruby-full build-essential gem -y && gem install bundler
Next, while in this repo, run:
bundle install
bundle exec jekyll serve
If you get an error on bundle install, you may need to change your gem path with bundle config set path ~/.gem. You may also need to delete Gemfile.lock to escape dependency hell.
And the site should be up!