diff --git a/Gemfile b/Gemfile
index 2de75c187..1cf065ceb 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,4 @@
+#ruby=1.9.3
 source 'https://rubygems.org'
 
 # Look for $WORKSPACE, otherwise use "workspace" as dev path.