ddns scripts updated

scripts/ddns/duckdns/install.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+thisdir="$( dirname "$(readlink -e -- "${BASH_SOURCE[0]}")")"
+
+# https://www.duckdns.org/install.jsp
+
+croncmd="$thisdir/update.sh"
+cronjob="*/30 * * * * $croncmd" # every 30 min
+( crontab -l | grep -v -F "$croncmd" ; echo "$cronjob" ) | crontab -
+cp -f "$thisdir/.env.example" "$thisdir/.env"