Work around travis-ci/travis-ci/issues/9333 with latest ruby

kpaulisse · kpaulisse · commit 178f7cbdf508 · 2018-03-29T10:50:25.000-04:00
diff --git a/.travis.yml b/.travis.yml
@@ -3,6 +3,7 @@
 language: ruby
 install: true
 script: "script/cibuild"
+before_install: gem install bundler
 
 matrix:
   include:
