.travis.yml in doit-0.3.0 vs .travis.yml in doit-0.3.2

@@ -1,8 +1,12 @@
 language: ruby
 sudo: false
+
 rvm:
-  - 2.0.0
-  - 2.2.3
+  - 2.5.0
+  - 2.4.1
+  - 2.3.0
+#  - 2.2.3  # tested; no longer in CI
+#  - 2.0.0  # tested; no longer in CI
 
 notifications:
   email: false