I’ve been running a TrinityCore instance in a docker container for a few months, and decided to write up my build / maintenance scripts and put them on github @ https://github.com/notagamedevnono/trinityCore-docker
My aim was to write a single build script that was relatively easy to set up and which did everything for you with minimal fuss - tool setup, building, client extraction, and docker building all in one. I also added a guide for how to run a docker instance, as there some settings which make it easier. Hopefully someone finds this useful. Feedback welcome.