.travis.yml in roo_on_rails-1.1.0 vs .travis.yml in roo_on_rails-1.2.0

@@ -1,14 +1,25 @@
 sudo: false
 language: ruby
 rvm:
+  - 2.2.6
   - 2.3.3
   - 2.4.0
+  - ruby-head
+gemfile:
+  - gemfiles/rails_3.gemfile
+  - gemfiles/rails_4.gemfile
+  - gemfiles/rails_5.gemfile
 install:
   - bundle install --jobs=3 --retry=3 --path=vendor/bundle
 cache:
   bundler: false
   directories:
     - vendor/bundle
 before_script:
   - unset RACK_ENV
   - unset RAILS_ENV
+matrix:
+  allow_failures:
+    - rvm: ruby-head
+    - rvm: 2.4.0
+      gemfile: gemfiles/rails_3.gemfile