Add sleuth to "Distributed Systems" section.

README.md

@@ -338,6 +338,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
 * [micro](https://github.com/micro/micro) - A pluggable microservice toolkit and distributed systems platform.
 * [NATS](https://github.com/nats-io/gnatsd) - A lightweight, high performance messaging system for microservices, IoT, and cloud native systems.
 * [raft](https://github.com/hashicorp/raft) - Golang implementation of the Raft consensus protocol, by HashiCorp.
+* [sleuth](https://github.com/ursiform/sleuth) - A library for master-less p2p auto-discovery and RPC between HTTP services (using [ZeroMQ](https://github.com/zeromq/libzmq)).
 * [torrent](https://github.com/anacrolix/torrent) - BitTorrent client package.
     * [dht](https://godoc.org/github.com/anacrolix/torrent/dht) - BitTorrent Kademlia DHT implementation.
     * [go-peerflix](https://github.com/Sioro-Neoku/go-peerflix) - Video streaming torrent client.