.travis.yml in watir-performance-0.5.2 vs .travis.yml in watir-performance-0.5.3

@@ -1,10 +1,21 @@
 sudo: required
 language: ruby
 
 matrix:
   include:
+
+  - os: linux
+    rvm: 2.6.0-preview1
+    addons:
+      chrome: stable
+      firefox: "59.0.2"
+    before_install:
+    - bash ./spec/support/setup-chromedriver.sh
+    - bash ./spec/support/setup-geckodriver.sh
+    - gem install bundler -v 1.16.1
+    script: xvfb-run bundle exec rake
   
   - os: linux
     rvm: 2.5.1
     addons:
       chrome: stable
@@ -12,21 +23,32 @@
     before_install:
     - bash ./spec/support/setup-chromedriver.sh
     - bash ./spec/support/setup-geckodriver.sh
     - gem install bundler -v 1.16.1
     script: xvfb-run bundle exec rake
-    
+
   - os: linux
-    rvm: 2.5.0
+    rvm: 2.4.4
     addons:
       chrome: stable
       firefox: "59.0"
     before_install:
     - bash ./spec/support/setup-chromedriver.sh
     - bash ./spec/support/setup-geckodriver.sh
     - gem install bundler -v 1.16.1
     script: xvfb-run bundle exec rake
+
+  - os: linux
+    rvm: 2.3.7
+    addons:
+      chrome: stable
+      firefox: "59.0"
+    before_install:
+    - bash ./spec/support/setup-chromedriver.sh
+    - bash ./spec/support/setup-geckodriver.sh
+    - gem install bundler -v 1.16.1
+    script: xvfb-run bundle exec rake
     
   - os: osx
     rvm: 2.5.1
     addons:
       chrome: beta
@@ -37,10 +59,22 @@
     - sudo safaridriver --enable
     - gem install bundler -v 1.16.1
     script: xvfb-run bundle exec rake
 
   - os: osx
-    rvm: 2.5.0
+    rvm: 2.4.4
+    addons:
+      chrome: beta
+      firefox: "59.0"
+    before_install:
+    - sudo bash ./spec/support/setup-chromedriver.sh
+    - sudo bash ./spec/support/setup-geckodriver-alt.sh
+    - sudo safaridriver --enable
+    - gem install bundler -v 1.16.1
+    script: xvfb-run bundle exec rake
+
+  - os: osx
+    rvm: 2.3.7
     addons:
       chrome: beta
       firefox: "59.0"
     before_install:
     - sudo bash ./spec/support/setup-chromedriver.sh