.travis.yml in rest-in-peace-6.0.3 vs .travis.yml in rest-in-peace-6.0.4

@@ -3,20 +3,34 @@
 rvm:
   - 2.0.0
   - 2.1.2
   - 2.2.5
   - 2.3.1
+  - 2.3.4
+  - 2.4.1
 gemfile:
   - gemfiles/Gemfile.activemodel-3.2.x
   - gemfiles/Gemfile.activemodel-4.0.x
   - gemfiles/Gemfile.activemodel-4.1.x
   - gemfiles/Gemfile.activemodel-4.2.x
   - gemfiles/Gemfile.activemodel-5.0.x
+  - gemfiles/Gemfile.activemodel-5.1.x
 script:
   - bundle exec rake spec
 before_install: gem install bundler
 matrix:
   exclude:
     - rvm: 2.0.0
       gemfile: gemfiles/Gemfile.activemodel-5.0.x
     - rvm: 2.1.2
       gemfile: gemfiles/Gemfile.activemodel-5.0.x
+    - rvm: 2.0.0
+      gemfile: gemfiles/Gemfile.activemodel-5.1.x
+    - rvm: 2.1.2
+      gemfile: gemfiles/Gemfile.activemodel-5.1.x
+notifications:
+  email: false
+  slack:
+    on_success: always
+    on_failure: always
+    rooms:
+      secure: VKDJrfgm1c9OUaQPyMutsVzMCwZzBQh7qxVGJnsdNOHOLtVrc6dQrC6+w7Zc1Py5H5pUU+roKi2n5rVnhNjHf4xukGEdDpI0JBBgYSZjl9b/RbxBsHYG9Z8tUQ0EZ7Bd9H3eH2LHQvjoEcvvUJ6I2BCbXlPCrMovfEB3ILQ8Ryo=