Update .travis.yml

* add more versions
* use addons: chrome

Author: workgena

.travis.yml

@@ -1,13 +1,18 @@
+sudo: required
+language: ruby
+addons:
+  chrome: stable
+
+before_install: gem install bundler -v 1.16.0.pre.3
+
 script: bundle exec rspec spec
-cache: bundler
+
 env:
   matrix:
-    - RAILS=4.2.6 AA=1.1.0
-    - RAILS=5.0.0 AA=1.2.1
+    - RAILS=4.2.10 AA=1.1.0
+    - RAILS=5.1.0 AA=1.2.1
+    - RAILS=5.2.1 AA=1.3.1
 rvm:
-  - 2.2.6
-  - 2.3.3
-before_install:
-  - gem update --system
-  - rvm @global do gem install bundler -v 1.14.6
-  - gem --version
+  - 2.3
+  - 2.4
+  - 2.5