This website is built using Middleman (http://middlemanapp.com), Sass, Compass and a few node modules. All the dependencies are automatically installed with the help of Bundler (http://bundler.io/) and npm.
If you don't have bundler installed, first do:
$ gem install bundler
Then, do the following to install dependencies:
$ bundle
$ npm install
Make your changes to the site in the source/ folder.
rake build
cd build
rackup config.ru -p 2000
Preview your changes in browser by pointing to http://localhost:2000
There is a little bash script that collects and compresses all the files and adds the new version number on the site.
$ ./build-marionette v2.0.1
rake deploy