diff --git a/package_ruby b/package_ruby
index 5e39d1064..65731589b 100755
--- a/package_ruby
+++ b/package_ruby
@@ -10,8 +10,21 @@ bundle gem jampb > /dev/null
 # copy over built ruby code
 cp src/*.rb jampb/lib/jampb
 
+if [ -z $BUILD_NUMBER ]; then
+        BUILD_NUMBER="1"
+fi
+
+VERSION="0.0.${BUILD_NUMBER}"
+
 pushd jampb > /dev/null
 
+cat > lib/jampb/version.rb << EOF
+module Jampb
+  VERSION = "$VERSION"
+end
+EOF
+
+
 # define gemspec
 cat >> jampb.gemspec << EOF