language: node_js

matrix:
  include:
  - node_js: '11'
    os: linux
  - node_js: '10'
    os: linux
  - node_js: '8'
    os: linux
  - node_js: '6'
    os: linux
  - node_js: '11'
    os: osx
  - node_js: '10'
    os: osx
  - node_js: '8'
    os: osx
  - node_js: '6'
    os: osx