Test with new rubies

Author: rafaelfranca

.travis.yml

@@ -6,9 +6,10 @@ rvm:
   - 2.0.0
   - 2.1.10
   - 2.2.10
-  - 2.3.7
-  - 2.4.4
-  - 2.5.1
+  - 2.3.8
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3
   - ruby-head
 env:
   - RAILS_VERSION="~> 4.2.0"
@@ -35,6 +36,8 @@ matrix:
       env: RAILS_VERSION="~> 5.2.0"
     - rvm: 2.1.10
       env: RAILS_VERSION="~> 5.2.0"
+    - rvm: 2.6.3
+      env: RAILS_VERSION="~> 4.2.0"
   allow_failures:
     - rvm: ruby-head
   fast_finish: true