anchor.diff:      && apt-get update && apt-get install -y \
           gcc \
           libpq-dev \
  +    && apt-get clean \
  +    && rm -rf /var/lib/apt/lists/* \
       && pip install gsutil
   
   RUN CLOUDSDK_CORE_DISABLE_PROMPTS=1 \
  
positive.code: RUN apt-get update \
      && curl -sL https://deb.nodesource.com/setup_8.x | bash - \
      && apt-get install -y \
          nodejs
  
  # install database clients for debugging (https://www.postgresql.org/download/linux/debian/)
  RUN echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list \
  
negative.code:     && apt-get update && apt-get install -y \
          postgresql \
          postgresql-client \
          libpq-dev \
      && apt-get clean \
      && rm -rf /var/lib/apt/lists/*
  
  RUN apt-get update && apt-get install -y \
      redis-tools \
      && apt-get clean \
      && rm -rf /var/lib/apt/lists/*
  
  # install gcloud tools
  RUN CLOUDSDK_CORE_DISABLE_PROMPTS=1 \
  