You just need docker to be able to set up the development environment.
Run:
docker-compose up
and go to localhost:4000 in your browser. Every time you make a change to one of the html, scss, js files jekyll will compile these files for you. Just refresh your browser and see the changes.
For deployment you need to add a JEKYLL_GITHUB_TOKEN to the .env file (remove the .example part). After you've done that you just need to run:
make staging
You need to have your private key id_rsa in the project root directory. Then run
docker build . -t iaeste-lc-kiel-website:latest && docker run iaeste-lc-kiel-website:latest ./scripts/production.sh
to deploy a new version of the website.