.travis.yml in fixer_upper-0.3.0 vs .travis.yml in fixer_upper-0.4.0

@@ -1,5 +1,18 @@
 sudo: false
 language: ruby
 rvm:
   - 2.4.0
-before_install: gem install bundler -v 1.14.6
+  - 2.3
+  - 2.2
+  - 2.1
+  - ruby-head
+cache: bundler
+before_install:
+  - gem install bundler -v 1.15.0
+notifications:
+  email: false
+matrix:
+  fast_finish: true
+  allow_failures:
+    - rvm: ruby-head
+    - rvm: 2.1