The main page says enough about HVARC…
Site maintained by Scott Onson KD9GBJ. To contribute, you must be a write-access member of the HVARC organization on GitHub.
Jekyll uses the Markdown syntax and Ruby to generate blog sites. GitHub Pages is very compatible with Jekyll and has it as its primary engine - using Ruby in the background to generate HTML based on the markdown entered.
See this introductory post about the engine for instructions on how to add a post. This must be done via Forking the repo to your personal domain, then submitting a pull request.