Assuming you have RubyGems and NPM installed:
$ cd website/
$ sudo gem install bundler
$ bundle install --path=vendor/bundle
$ npm install
$ cd ../libhaliteviz
$ npm install
$ cd ../website
$ npm run build
$ bundle exec jekyll serve
Then visit http://localhost:4000.
If you modify the JavaScript, you might want to run the Webpack watcher, which will rebuild the JavaScript bundle on the fly:
$ npm run watch
To deploy, You will also want a folder with compiled Halite environment binaries. The binaries should be named after the platform they are for, e.g. MacOS, Linux-x64, and Windows.exe. Run make_starter_kits.py to generate all the starter kits and source downloads.
Currently, there is no automation for building the offline visualizer.
$ # Make sure to kill Jekyll and Webpack beforehand, if they're running
$ python3 make_starter_kits.py path/to/folder/with/compiled/halite/environments
$ npm run build
$ bundle exec jekyll build