.travis.yml in smart_engine-0.5.0 vs .travis.yml in smart_engine-0.6.0

@@ -1,19 +1,20 @@
 ---
 language: ruby
 cache: bundler
-before_install: gem install bundler -v 2.1.2
+before_install: gem install bundler
 os: linux
+dist: xenial
 script:
 - bundle exec rake rubocop
 - bundle exec rake rspec
 jobs:
   fast_finish: true
   include:
-  - rvm: 2.4.9
-  - rvm: 2.5.7
-  - rvm: 2.6.5
-  - rvm: 2.7.0
+  - rvm: 2.4.10
+  - rvm: 2.5.8
+  - rvm: 2.6.6
+  - rvm: 2.7.1
   - rvm: ruby-head
   - rvm: jruby-head
   allow_failures:
   - rvm: ruby-head
   - rvm: jruby-head