Merge pull request #220 from olleolleolle/patch-1

Travis: jruby-9.1.13.0

Author: hsbt

.travis.yml

@@ -7,7 +7,7 @@ rvm:
   - 2.3.4
   - 2.4.1
   - ruby-head
-  - jruby-9.1.12.0
+  - jruby-9.1.13.0
   - jruby-head
 before_install:
   - gem install bundler --no-document -v '~> 1.13.3'