.travis.yml in appbundler-0.11.3 vs .travis.yml in appbundler-0.11.4

@@ -1,14 +1,21 @@
+language: ruby
+cache: bundler
+dist: trusty
+
 before_install:
   - gem update --system
   - gem install bundler
 
 rvm:
-  - 2.2.5
-  - 2.3.1
+  - 2.4.4
+  - 2.5.1
 
 branches:
   only:
     - master
+
+install:
+  - bundle install --jobs 3 --retry 3
 
 # The integration tests need to see installed gems.
 script: rspec --color --format progress