Bring RFC2136 doc reference to front page

Signed-off-by: Yury Tsarev <yury@upbound.io>

README.md

@@ -106,6 +106,7 @@ Internal k8gb architecture and its components are described [here](/docs/compone
 * [AWS based deployment with NS1 integration](/docs/deploy_ns1.md)
 * [Azure based deployment with Windows DNS integration](/docs/deploy_windowsdns.md)
 * [General deployment with Cloudflare integration](/docs/deploy_cloudflare.md)
+* [Seamless DDNS Integration with Bind9 and other RFC2136-Compatible DNS Environments](/docs/provider_rfc2136.md)
 * [Local playground for testing and development](/docs/local.md)
 * [Local playground with Kuar web app](/docs/local-kuar.md)
 * [Metrics](/docs/metrics.md)