anchor.diff:  ENV NODE_ENV $NODE_ENV
   
   COPY package.json /usr/src/app/
  -COPY yarn.lock /usr/src/app/
  +## COPY yarn.lock /usr/src/app/
   
   # replacement for npm install
  -RUN yarn
   RUN yarn/dist/bin/yarn --verbose
   COPY . /usr/src/app
   
  
positive.code: 
  ENV yarnVersion 0.19.1
  
  RUN mkdir -p /usr/src/app
  WORKDIR /usr/src/app
  RUN mkdir -p yarn && cd yarn && \
    wget https://github.com/yarnpkg/yarn/releases/download/v$yarnVersion/yarn-v$yarnVersion.tar.gz && \
    tar xzf yarn-v$yarnVersion.tar.gz && rm yarn-v$yarnVersion.tar.gz && pwd && ls -l
  
negative.code: FROM node:6.2.2
  
  RUN mkdir -p /usr/src/app
  WORKDIR /usr/src/app
  
  # It was set to info, which enables
  # log output for downloading dependencies.
  