take a Raspberry PI 4 ram4 or ram8 
then take one MicroSD (INDUSTRIAL) up Amazzon… Ebay…
write on Docker dal sito: https://blog.hypriot.com/ 
precisely to the section: Download, latest version.
once the image is written to SD, insert in the Raspberry PI and connect away SSH (Username Password for Docker SSH I’m: “pirate” “hypriot” → (User: pirate) (Pass: hypriot).) obviously after connecting SSH change the credentials to your liking from → sudo raspi-config, restart Raspberry.
once restarted, connect with SSH and install “Discourse” following this guide: https://linoxide.com/how-tos/install-discourse-docker-container/ obviously you will start from the point 2) because Docker you installed it right from the start.
good fun.