language: ruby
cache:
  directories:
    - bundle

rvm:
  - 2.0
  - 2.1.3
  - 2.3.1

script:
    - bundle exec rake spec
language: ruby
cache:
  directories:
    - bundle

rvm:
  - 2.0
  - 2.1.3
  - 2.3.1

before_install:
  - gem update bundler

script:
    - bundle exec rake spec

Add `gem update bundler` to before_install
:green_heart: Add `gem update bundler` to before_install

Prevent "NoMethodError: undefined method `spec' for nil:NilClass" on Travis CI jobs.
