sudo: false
language: ruby
rvm:
  - 2.2.0
  - 2.3.0
  - 2.4.0
  - 2.5.0
  - ruby-head
before_install: gem install bundler -v 1.15.4

sudo: false
language: ruby
rvm:
  - 2.3.0
  - 2.4.0
  - 2.5.7
  - 2.6.0
  - 2.7.0
  - ruby-head
before_install: gem install bundler -v "$(grep -A 1 "BUNDLED WITH" Gemfile.lock | tail -n 1)"

Add CI testing for ruby versions 2.6 and 2.7.
Add CI testing for ruby versions 2.6 and 2.7.

Update Travis CI script to install correct version of bundler.
