anchor.diff:  # Install git so that Composer, when fetching dev dependencies, can do a 'git clone'
   # Install a database client, which is used by 'drush up' and 'drush sql-dump'
   #   mysql-client or sqlite3
  -# Install ruby for 'gem install sass'
  +# Install ruby and ruby-dev for 'gem install sass'
   # Install self-signed SSL (auto-generated) for HTTPS
   # Install supervisor so we can run multiple processes in one container
  -RUN apt-get -y update
  -RUN apt-get -y install \
  +RUN apt-get -y update && \
  +    apt-get -y install \
           gawk \
           git \
           mysql-client \
  -        ruby \
  +        ruby ruby-dev \
           sqlite3 \
           ssl-cert openssl-blacklist \
  -        supervisor
  -RUN gem install sass
  +        supervisor && \
  +    gem install sass
   
   ############## Nginx 1.11.5
   # - skips installing nginx-module-*
  
positive.code: # Writing Guidelines: https://docs.docker.com/engine/userguide/eng-image/dockerfile_best-practices/
  # vim: set tabstop=4 shiftwidth=4 expandtab :
  
  FROM drupal:8.2.5-fpm
  
  MAINTAINER Jonah.Beckford@plainlychrist.org
  
  WORKDIR /var/www/html
  
  ############# Versions
  
  # https://hub.docker.com/_/nginx/ 1.11.5
  ENV NGINX_VERSION 1.11.5-1~jessie
  ENV DRUSH_MAJOR_VERSION 8
  ENV VIDEO_EMBED_FIELD_VERSION ^1.4
  ENV SYMFONY_INTL_VERSION ^3.2
  ENV SYMFONY_FORM_VERSION ^3.2
  ENV DRUPAL_WORKBENCH_MODERATION_VERSION ^1.2
  ENV DRUPAL_BACKUP_DB_VERSION ^1.0
  ENV DRUPAL_ADVAGG ^2.0
  ENV DRUPAL_BOOTSTRAP_VERSION ^3.1
  ENV MYSQL2SQLITE_VERSION 1b0b5d610c6090422625a2c58d2c23d2296eab3a
  # This, as of 9/8/2016, is a dev dependency (https://packagist.drupal-composer.org/packages/drupal/security_review#dev-8.x-1.x), which needs 'git clone'
  ENV DRUPAL_SECURITY_REVIEW_VERSION 1.x-dev
  ENV DRUPAL_NAME_VERSION 1.x-dev
  ENV DRUPAL_ADDRESS_VERSION 1.x-dev
  
  # https://developers.google.com/speed/pagespeed/module/release_notes
  ENV NPS_VERSION 1.11.33.4
  
  ########################
  ######## ROOT ##########
  
negative.code: 
  # Clean up space and unneeded packages (we don't need SASS and hence Ruby anymore)
  
  RUN gem cleanup all && \
          apt-get -y remove ruby && \
          apt-get autoremove -y && \
          apt-get clean && \
  