.travis.yml in textbringer-0.2.7 vs .travis.yml in textbringer-0.2.8

@@ -2,32 +2,40 @@
 matrix:
   include:
     - os: linux
       dist: trusty
       sudo: false
-      rvm: 2.3.4
+      rvm: 2.3.5
     - os: linux
       dist: trusty
       sudo: false
-      rvm: 2.4.1
+      rvm: 2.4.3
     - os: linux
       dist: trusty
       sudo: false
+      rvm: 2.5.0
+    - os: linux
+      dist: trusty
+      sudo: false
       rvm: ruby-head
     - os: osx
       osx_image: xcode8.2
-      rvm: 2.3.3
+      rvm: 2.3.5
     - os: osx
       osx_image: xcode8.2
-      rvm: 2.4.0
+      rvm: 2.4.3
     - os: osx
       osx_image: xcode8.2
+      rvm: 2.5.0
+    - os: osx
+      osx_image: xcode8.2
       rvm: ruby-head
   allow_failures:
     - os: osx
     - rvm: ruby-head
   fast_finish: true
 cache: bundler
+before_install: gem update --system
 script:
   - if [ "$TRAVIS_OS_NAME" == "linux" ]; then
         xvfb-run bundle exec rake test;
     else
         bundle exec rake test;