add update-site script

Author: decebals

update-site.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# go to the gh-pages branch
+git checkout gh-pages
+
+# bring gh-pages up to date with master
+git rebase master
+
+# commit the changes
+git push origin gh-pages
+
+# go back to the master branch
+git checkout master