title: Unreachable rails application in simple docker container
body: <p>I have a simple docker image with a bare-bones rails app defined in it.</p>
  
  <p>When I run...</p>
  
  <pre><code>$ docker build myimage .
  $ docker run -p 3000:3000 myimage
  </code></pre>
  
  <p>...and then run... </p>
  
  <pre><code>curl http://localhost:3000 
  </code></pre>
  
  <p>...I get the expected response right back</p>
  
  <p>However, when I run...</p>
  
  <pre><code>$ docker-compose up
  </code></pre>
  
  <p>...where my Dockerfile is the same as I used to create the image, the output indicates that the rails app is started and listening BUT when I run the same curl command I get no response, and the app shows no indication it has been reached. If I stop the container I get a "connection reset" from curl, which indicates it was somehow connected. (OR if I wait long enough with curl command hanging, I eventually get the same "connect reset" message.</p>
  
  <p>EDIT: I noticed that the <code>docker-compose up</code> command's output does not include "Creating network...with the default driver"</p>
  
  <p>Any ideas on how I might troubleshoot this?</p>
  
  <p>Thanks</p>
  
  <p>This is my docker-compose.yml...</p>
  
  <pre><code>version: '3'
    services:
      web:
        build: .
        ports:
          - "3000:3000"
  </code></pre>