lib/utils.sh: add description and licensing info

diff --git a/lib/utils.sh b/lib/utils.sh
index 4d45cdb..f693c53 100755 (executable)
--- a/lib/utils.sh
+++ b/lib/utils.sh
@@ -1,5 +1,10 @@
 #!/bin/sh
 #
+# Some utility functions to keep iptables and ip6tables configuration in sync.
+#
+# Copyright (C) 2018  Antonio Ospite <ao2@ao2.it>
+# SPDX-License-Identifier: MIT
+#
 # Based on updateipt.sh by Phil Sutter:
 # https://developers.redhat.com/blog/2017/01/10/migrating-my-iptables-setup-to-nftables/