anchor.diff:  
   ADD docker-entrypoint.sh /
   
  +RUN apt-get update && \
  +  apt-get install \
  +  apt-transport-https \
  +  ca-certificates \
  +  curl \
  +  software-properties-common
  +
  +RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add - && \
  +  apt-key fingerprint 0EBFCD88
  +
  +RUN add-apt-repository \
  +   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
  +   $(lsb_release -cs) \
  +   stable"
  +
  +RUN apt-get update && apt-get install docker-ce
  +
   RUN ["chmod", "+x", "/docker-entrypoint.sh"]
   
  -ENTRYPOINT ["wrapdocker"]
   ENTRYPOINT ["/docker-entrypoint.sh"]
  
positive.code: # regardless of whatever dependencies get added
    addgroup -g 1001 go && \ 
    adduser -D -u 1001 -G go go && \
    adduser go docker && \
    apk --update-cache upgrade && \ 
    apk add --update-cache openjdk8-jre-base git mercurial subversion openssh-client bash && \
  # unzip the zip file into /go-agent, after stripping the first path prefix
  
negative.code: FROM ubuntu:16.04
  
  LABEL gocd.version="17.7.0" \
    gocd.full.version="17.7.0-5147" \
    gocd.git.sha="53fdb1b15184f93966059a42429bf9ed0bfdee59"
  
  ADD "https://download.gocd.org/binaries/17.7.0-5147/generic/go-agent-17.7.0-5147.zip" /tmp/go-agent.zip
  ADD https://github.com/krallin/tini/releases/download/v0.14.0/tini-static-amd64 /usr/local/sbin/tini
  