Best practices to test a web app and share the obtained image

Hello,
I’m new with Docker and want to test the opensource webapp Waterbear (http://waterbear.info), which runs with Apache/MySQL/PHP.
As this could interest other people, I would like to share the image I will obtain, but I don’t know which are the steps to this goal.
Are there best practices to do this ? (Which image should I begin with ? Should I use a Docker file ? …)