.travis.yml in redcarpet-render-html_lazy_img-0.1.0 vs .travis.yml in redcarpet-render-html_lazy_img-0.2.0

@@ -1,7 +1,13 @@
 ---
 sudo: false
 language: ruby
 cache: bundler
 rvm:
-  - 2.6.4
+  - 2.4
+  - 2.5
+  - 2.6
+  - ruby-head
 before_install: gem install bundler -v 2.0.2
+matrix:
+  allow_failures:
+  - rvm: ruby-head