Install most recent bundler to fix build on Ruby 1.9.3

dalibor · dalibor · commit 6cd9c10d9c03 · 2017-04-18T15:09:11.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,3 +1,5 @@
+before_install:
+  - gem install bundler
 rvm:
   - "2.1.5"
   - "2.1.4"
