Update the readme file.

README.md

@@ -1956,6 +1956,13 @@ command. Sample return dictionary:
 	  "result": "ok"
 	}
 
+The *tcp-ng* Control Protocol
+=========================
+
+*rtpengine* also has support for *ng* control protocol where transport is
+TCP (If enabled in the config via the --listen-tcp-ng option). Everything
+said for UDP based *ng* protocol counts for TCP variant too.
+
 HTTP/WebSocket support
 ======================