Dock

FROM elixir:1.6.1
RUN mix local.hex --force

ENV WORKDIR /app
WORKDIR $WORKDIR

COPY mix.exs mix.lock $WORKDIR/
RUN mix deps.get
RUN mix deps.compile

COPY . ./
ENTRYPOINT mix run --no-halt

docker-compose.yml

version: "3"

services:
  app:
    build:
      context: .
    ports:
      - "4000:4000"
    volumes:
      - .:/app
    command: "mix run --no-halt"