title: AWS beanstalk not building docker container
body: <p>Part of my docker-compose.yaml file is:</p>
  
  <pre><code>version: '3'
  services:
    nginxProxy:
      image: nginxproxy
      build:
        context: ./dockerfiles/nginxproxy/
  </code></pre>
  
  <p>When trying to run an elastic beanstalk environment with this, I get an error of:</p>
  
  <blockquote>
    <p>ECS task stopped due to: Essential container in task exited.
    (nginxProxy: CannotPullContainerError: API error (404): repository
    nginxproxy not found: does not exist or no pull access httpdbin: )</p>
  </blockquote>
  
  <p>Does Elastic Beanstalk support building docker images?</p>