.travis.yml in kindle_manager-0.1.2 vs .travis.yml in kindle_manager-0.1.3

@@ -1,7 +1,7 @@
 sudo: false
 language: ruby
 rvm:
-  - 2.2.4
-  - 2.2.6
-  - 2.3.3
+  - 2.2.7
+  - 2.3.4
+  - 2.4.1
 before_install: gem install bundler -v 1.14.6