Here is an example of a custom Docker configuration for a (not that) simple PHP project, for the dev environment. We use docker-compose to set up everything together.
I keep many of the config files we have to give a more realistic example. But you shouldn't simply copy them, because it won't fit your project.
The Makefile contains examples of shortcut commands that we have set for our
non-docker-friendly devs. It will show you how we do interact with our docker
env.
The docker-compose.yml file, the Makefile and the .docker folder are
located at the root of our project sources.