To start:

docker-compose build (to build)
docker-compose run --rm --service-ports web  (to run server in debugging mode - you can use IEx.pry ;))

General phoenix app steps:

• Install dependencies with mix deps.get
• Create and migrate your database with mix ecto.create && mix ecto.migrate
• Install Node.js dependencies with npm install
• Start Phoenix endpoint with docker-compose up
• If you need to debug with iex.pry use 'docker-compose run -e "DEBUG=true" --rm --service-ports web'

Now you can visit localhost:3000 from your browser. (if you have port forwarding.)