Add installation script for dns-updater service

install

@@ -0,0 +1,13 @@
+#!/usr/bin/bash
+
+if [[ $(id -u) -ne 0 ]]; then
+    echo "This script must be run as root" >&2
+    exit 1
+fi
+
+mkdir -p /opt/dns-updater
+cp app.py /opt/dns-updater/
+cp dns-updater.service /etc/systemd/system/
+systemctl daemon-reload
+systemctl enable --now dns-updater.service
+systemctl status dns-updater.service