How to add new page into biggis-docs

biggis-docs-new-page-howto.md

# install required stuff (you should have already installed it anyways)
pip install --user mkdocs
pip install --user mkdocs-material
sudo apt install nodejs

# clone the repo
git clone https://github.com/biggis-project/biggis-docs.git
cd biggis-docs

# add new section and serve the generated docs
echo "# Firefighting" > docs/demos/firefighting.md
./fix-mkdocs-pages.sh
mkdocs serve