.travis.yml in validates_cpf-3.0.0 vs .travis.yml in validates_cpf-3.1.0

- old
+ new
@@ -1,10 +1,37 @@
-rvm:
-  - 2.2
-  - 2.3
-  - 2.4
-  - 2.5
-gemfile:
-  - gemfiles/Gemfile.rails4
-  - gemfiles/Gemfile.rails5
-before_script:
-  - bundle exec rubocop
\ No newline at end of file
+matrix:
+  include:
+    - rvm: 2.2
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.2
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.3
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.3
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.4
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.4
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.5
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.5
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.5
+      gemfile: gemfiles/Gemfile.rails6
+    - rvm: 2.6
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.6
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.6
+      gemfile: gemfiles/Gemfile.rails6
+    - rvm: 2.7
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 2.7
+      gemfile: gemfiles/Gemfile.rails5
+    - rvm: 2.7
+      gemfile: gemfiles/Gemfile.rails6
+    - rvm: 3.0
+      gemfile: gemfiles/Gemfile.rails4
+    - rvm: 3.0
+      gemfile: gemfiles/Gemfile.rails6
+      script: rake complete