title: Docker - run two processes in single container
body: <p>I've created Ruby on Rails project with Nginx. Rails app and Nginx runs in separate and linked containers. This configuration works fine. However...</p>
  
  <p><strong>1) Is it possible to run both together (Rails / Puma server + Nginx) in a single container?</strong> </p>
  
  <p><strong>2) How should the CMD command in Dockerfile look like?</strong></p>
  
  <p><strong>3) What command should I use as the "command:" attribute in docker-compose.yml?</strong></p>
  
  <p>I think that configuration to run them in separate containers is better solution, but I would like to get to know all possibilites.</p>
  
  <p><em>I use Puma as a Rails' app server and to run it I use command: bundle exec puma -C config/puma.rb</em></p>