.travis.yml in rails_multitenant-0.5.2 vs .travis.yml in rails_multitenant-0.6.0

- old
+ new

@@ -1,9 +1,10 @@
 language: ruby
 sudo: false
 env:
   - RAILS_VERSION="~> 4.1.16"
-  - RAILS_VERSION="~> 4.2.7"
-  - RAILS_VERSION="~> 5.0.0"
+  - RAILS_VERSION="~> 4.2.9"
+  - RAILS_VERSION="~> 5.0.4"
+  - RAILS_VERSION="~> 5.1.2"
 rvm:
-  - 2.3.1
-before_install: gem install bundler -v 1.12.5
+  - 2.3.4
+before_install: gem install bundler -v 1.15.2