title: Create Docker image from existing Ubuntu + App
body: <p>I installed Moodle (eLearning PHP based app, but it could be any app) locally on Ubuntu and would like to package it as Docker image/container. There were whole bunch of installations and configurations done. I'd like to package all that so that I can deploy to some Docker enabled hosting service, such as Digital Ocean or AWS.</p>
  
  <p>How do I create Docker image?</p>
  
  <p>Do I need to handle networking, ports and Apache configuration for production deployment?</p>