anchor.diff:  #
   # https://github.com/jorelcb/nginx-debian
   #
  +# Pull base image.
  +FROM debian:jessie
   
  -# Pull base image.
  -FROM debian:latest
  -
  -MAINTAINER Jorge Corredor "jorel.c@gmail.com"
  +MAINTAINER "Jorge Corredor" <jorel.c@gmail.com>
   
   # Install Nginx.
   
  
positive.code: RUN apt-get install -y \
      ca-certificates \
      nginx=${NGINX_VERSION} && \
      rm -rf /var/lib/apt/lists/* && \
      echo "\ndaemon off;" >> /etc/nginx/nginx.conf
  
  # forward request and error logs to docker log collector
  RUN ln -sf /dev/stdout /var/log/nginx/access.log
  RUN ln -sf /dev/stderr /var/log/nginx/error.log
  
  VOLUME ["/etc/nginx/sites-enabled", "/etc/nginx/certs", "/etc/nginx/conf.d", "/var/log/nginx", "/var/cache/nginx"]
  
  # Define working directory.
  WORKDIR /etc/nginx
  
  # Expose ports.
  EXPOSE 80
  EXPOSE 443
  
  # Define default command.
  CMD ["nginx"]
  
negative.code: RUN echo "deb http://nginx.org/packages/debian/ jessie nginx" >> /etc/apt/sources.list
  
  ENV NGINX_VERSION 1.8.0-1~jessie
  ENV DEBIAN_FRONTEND noninteractive
  
  # install dialog as ca-certificates prerequisite
  RUN apt-get update && \
  