Deploy a phoenix distilled app to jelastic with docker containers

I have a very small app that I try to deploy on jelastic. It's a phoenix app, connected to mysql. I use distillery and deploy it to jelastic using a docker container. I can't manage to get my app to connect to the database. Also I need to initialize the database with a dump. So the job is to manage to set the connexion to the database and any further steps need to have the app working.