title: Docker Elixir mix 'command not found'
body: <p>Trying to set up docker with a new Phoenix/Elixir app. I've shared the Dockerfile I'm using below.</p>
  
  <p>When I run <code>docker-compose up</code> with this Dockerfile, I get errors that say "mix does not exist". </p>
  
  <p>I'm working from this link. 
  <a href="https://medium.com/@hex337/running-a-phoenix-1-3-project-with-docker-compose-d82ab55e43cf" rel="nofollow noreferrer">https://medium.com/@hex337/running-a-phoenix-1-3-project-with-docker-compose-d82ab55e43cf</a></p>
  
  <p>Thanks!</p>
  
  <pre><code># Elixir + Phoenix
  
  FROM elixir:1.6.1
  FROM node:8.2
  
  # Install debian packages
  RUN apt-get update
  RUN apt-get install --yes build-essential inotify-tools postgresql-client
  
  # Install Phoenix packages
  
  RUN mix local.hex --force
  RUN mix local.rebar --force
  RUN mix archive.install --force https://github.com/phoenixframework/archives/raw/master/phx_new.ez
  
  
  WORKDIR /app
  EXPOSE 4000
  </code></pre>