Add initial update helper

Signed-off-by: Alejandro Mery <amery@geeks.cl>

update.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+cd "$(dirname "$0")"
+
+if [ "$(git ls-files -mdo)" ]; then
+	updated=true
+	git stash -q
+else
+	updated=false
+fi
+
+echo "== $PWD =="
+git pull -q --rebase
+
+if $updated; then
+	git stash pop -q
+fi
+
+[ $# -eq 0 ] || exec "$@"