update README.md

Author: Rain Liu

README.md

@@ -65,6 +65,8 @@
 ## Overview
 
 WebRTC.rs is a pure Rust implementation of WebRTC stack, which rewrites <a href="https://github.com/pion/webrtc/releases/tag/v3.0.32">Pion</a> stack in Rust.
+This project is still in active and early development stage, please refer to the [Roadmap](https://github.com/webrtc-rs/webrtc/issues/1) to track the major milestones and releases.
+[Examples](https://github.com/webrtc-rs/webrtc/tree/master/examples#readme) provide code samples to show how to use webrtc-rs to build media and data channel applications.
 
 ## Features