anchor.diff:      && npm install intern \
       && npm install -g mocha \
       && npm install -g eslint \
  -    && npm install ghooks --save-dev 
  +    && npm install ghooks --save-dev \
  +    && apt-get purge -y --auto-remove git-core \
  +    && rm -rf /var/lib/apt/lists/*
   
   # Define working directory.
   WORKDIR /var/www
  
positive.code: # eslint:   https://github.com/eslint/eslint
  # ghooks:   https://www.npmjs.com/package/ghooks
  RUN \
      npm install -g cnpm --registry=https://registry.npm.taobao.org \
      && npm install --global gulp \
      && npm install -g webpack \
  
negative.code:         libyaml-dev \
          procps \
          zlib1g-dev \
      && rm -rf /var/lib/apt/lists/*
  
  ENV RUBY_MAJOR 2.2
  