The site is hosted on Cloudflare with Cloudflare pages.
Update 08/06/2022:
Gatsby.js doesn't support node:12 anymore so I pushed my working image to tdhttt/digerini-website:1.0. To use the image, simply run docker pull tdhttt/digerini-website:1.0 && docker run tdhttt/digerini-website:1.0
To install all the node packages, run the gatsby dev docker with node as the user:
docker run -it -v $PWD:/app dev-gatsby
To develop it locally:
docker-compose up