Test on both Linux and OSX
diff --git a/.travis.yml b/.travis.yml
index 00b2b67..4bb6878 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,10 @@
   - 1.5.4
   - 1.6.2
   - tip
+  
+os:
+  - linux
+  - osx
 
 matrix:
   allow_failures: