title: Create files / folders on docker-compose build or docker-compose up
body: <p>I'm trying my first steps into Docker, so I tried making a Dockerfile that creates a simple index.html and a directory images (See code below)</p>
  
  <p>Then I run docker-compose build to create the image, and docker-compose-up to run the server. But I get no file index.html or folder images.</p>
  
  <p>This is my Dockerfile:</p>
  
  <pre><code>FROM php:apache
  MAINTAINER brent@dropsolid.com
  
  WORKDIR /var/www/html
  
  RUN touch index.html \
      &amp;&amp; mkdir images
  </code></pre>
  
  <p>And this is my docker-compose.yml</p>
  
  <pre><code>version: '2'
  services:
    web:
      build: .docker/web
      ports:
        - "80:80"
      volumes:
        - ./docroot:/var/www/html
  </code></pre>
  
  <p>I would expect that this would create a docroot folder with an image directory and an index.html, but I only get the docroot.</p>