Build the site with '_config.yml', add the 'build' action hook for OpenShift.

.openshift/action_hooks/build

@@ -0,0 +1,8 @@
+#!/bin/bash
+# This is a simple build script and will be executed on your CI system if
+# available.  Otherwise it will execute while your application is stopped
+# before the deploy step.  This script gets executed directly, so it
+# could be python, php, ruby, etc.
+
+cd $OPENSHIFT_REPO_DIR
+bundle exec jekyll build