anchor.diff:  
   # Build devevelopment image
   FROM        base as dev
  +LABEL       stage=build
   RUN         apt-get install -y --no-install-recommends --allow-unauthenticated \
               build-essential \
               gcc-7 \
  
positive.code: 
  # Base stage for building final images
  FROM        ruby:2.5-slim-buster as base
  RUN         echo 'APT::Default-Release "stretch";' > /etc/apt/apt.conf.d/99defaultrelease \
           && echo "deb     http://ftp.us.debian.org/debian/    testing main contrib non-free"  >  /etc/apt/sources.list.d/testing.list \
           && echo "deb-src http://ftp.us.debian.org/debian/    testing main contrib non-free"  >> /etc/apt/sources.list.d/testing.list \
  
negative.code: 
  # Build production gems
  FROM        bundle as bundle-prod
  LABEL       stage=build
  RUN         bundle install --without development test --with aws production postgres
  
  
  # Install node modules
  FROM        node:12-buster-slim as node-modules
  LABEL       stage=build
  RUN         apt-get update && apt-get install -y --no-install-recommends git
  COPY        package.json .
  COPY        yarn.lock .
  