.travis.yml in yoga-0.2.0 vs .travis.yml in yoga-0.2.1

@@ -1,8 +1,10 @@
 language: ruby
 rvm:
   - 2.4.0
   - 2.2.2
   - 2.1.0
+before_install: gem install bundler
+install: bundle install
 script:
   - bundle exec rubocop --format clang
   - bundle exec rspec spec