.travis.yml in tjson-0.4.0 vs .travis.yml in tjson-0.5.0

@@ -2,19 +2,25 @@
 sudo: false
 before_install: gem install bundler
 
 bundler_args: --without development doc
 
+script: bundle exec rake ci
+
 rvm:
+  - jruby-9.1.5.0
   - 2.0
   - 2.1
   - 2.2
   - 2.3.1
   - 2.4.1
-  - jruby-9.1.5.0
 
 matrix:
   fast_finish: true
+  include:
+  # Only run RuboCop on the latest Ruby
+  - env: SUITE="rubocop"
+    rvm: 2.4.1
 
 branches:
   only:
     - master