This webpage is based on the GDG Toulouse's webpage, which you can find here and its github repository here
The webpage is built with Jekyll; you will find explanations of how you install and build a website with Jekyll.
Please consult the following description if you want to setup a similar website locally:
https://help.github.com/articles/setting-up-your-github-pages-site-locally-with-jekyll/
Or if you want to publish the webpage, follow this description: