anchor.diff:  RUN bower install --production --allow-root
   RUN polymer build
   
  -COPY build/default /usr/share/nginx/html
  -
   # clean
   RUN npm uninstall -g bower
   RUN npm uninstall -g polymer-cli
   RUN apt-get purge -y curl git gnupg
   
  -EXPOSE 80
  +# prpl-server
  +RUN npm install -g prpl-server
  +
  +EXPOSE 8080
  +CMD ["prpl-server","--host", "0.0.0.0", "--root","build","--config","build/polymer.json"]
  
positive.code: FROM nginx
  
  RUN \
  apt-get update && \
  
negative.code: 
  # Install bower and gulp
  RUN npm install -g bower
  RUN npm install -g polymer-cli --unsafe-perm
  
  # Copy app
  ENV APP_HOME /myapp
  