language: node_js
node_js:
  - 6
  - 4
before_install:
  - npm i -g npm@latest

language: node_js
node_js:
  - 8
  - 6
  - 4
before_install:
  - npm i -g npm@5
  - install -g greenkeeper-lockfile@1
before_script: greenkeeper-lockfile-update
after_script: greenkeeper-lockfile-upload

Test with Node 8, add greenkeeper lock updater
Test with Node 8, add greenkeeper lock updater
