.travis.yml in rzo-0.7.0 vs .travis.yml in rzo-0.8.0

@@ -4,11 +4,11 @@
 
 notifications:
   email: false
 
 rvm:
-  - 2.1.9
-  - 2.4.1
+  - 2.4.4
+  - 2.5.1
 
 script:
   - 'bundle exec rake validate rubocop'
   - 'bundle exec rspec'
   - 'scripts/functional_gem_behavior.sh'