anchor.diff:  # Base stage for building gems
   FROM        ruby:2.5-buster as bundle
   LABEL       stage=build
  +LABEL       project=avalon
   RUN     echo "deb http://deb.debian.org/debian buster-backports main" >> /etc/apt/sources.list && \
           apt-get update && apt-get upgrade -y build-essential \
            && apt-get install -y --no-install-recommends \
  
positive.code: # Base stage for building final images
  FROM        ruby:2.5-slim-buster as base
  LABEL       stage=build
  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 assets
  FROM        base as assets
  LABEL       stage=build
  LABEL       project=avalon
  COPY        --from=bundle-prod --chown=app:app /usr/local/bundle /usr/local/bundle
  COPY        --chown=app:app . .
  COPY        --from=node-modules --chown=app:app /node_modules ./node_modules
  