language: ruby
services:
  - mongodb
before_install: gem install bundler -v 1.15.3
before_script: rake empty_dest
rvm:
  - 2.2.10
  - 2.3.7
  - 2.4.4
  - 2.5.1

language: ruby
services:
  - mongodb
before_install: gem install bundler
before_script: rake empty_dest
rvm:
  - 2.2.10
  - 2.3.7
  - 2.4.4
  - 2.5.1

Fix bundler gem install for Ruby >= 2.4
[CI] Fix bundler gem install for Ruby >= 2.4