anchor.diff: -FROM node:7
  +FROM node:7.8-alpine
   
   ENV NODE_ENV ${NODE_ENV:-development}
   ENV PORT ${PORT:-3333}
  
positive.code: COPY package.json yarn.lock ./
  
  # install dev dependences because they're used by yarn build
  RUN /bin/bash -c "NODE_ENV=development yarn"
  
  RUN npm rebuild node-sass
  RUN cd /usr/src/app/node_modules/nhsuk-frontend && npm run postinstall
  
negative.code: 
  RUN npm run build
  
  CMD [ "/bin/sh", "-c", "npm run start" ]
  