.travis.yml in how_is-24.0.0 vs .travis.yml in how_is-25.0.0

@@ -1,15 +1,18 @@
 language: ruby
 rvm:
-  - 2.3.3
-  - 2.4.1
-  - 2.5.0
+  - 2.4
+  - 2.5
+  - 2.6
   - ruby-head
 
 matrix:
   allow_failures:
     - rvm:
       - ruby-head
+
+before_install:
+  - gem install bundler
 
 # See https://bors.tech/documentation/getting-started/
 branches:
   only:
     # This is where pull requests from "bors r+" are built.