Add OS X to the test matrix

Author: sodabrew

.travis.yml

@@ -2,9 +2,7 @@ language: ruby
 bundler_args: --without benchmarks
 script:
   - bundle exec rake spec
-# Temporary workaround for broken Rubygems on Travis
 before_install:
-  - gem update --system 2.1.11
   - gem --version
   - |
     bash -c " # Install MariaDB if DB=mariadb
@@ -23,6 +21,9 @@ before_install:
     fi
     "
   - mysqld --version
+os:
+  - linux
+  - osx
 rvm:
   - 1.8.7
   - 1.9.2