update build readme

Author: crysislinux

README.md

@@ -17,6 +17,9 @@ I checked websocket clients in chrome web store and I am using Simple Websocket
 
 # Install && Build
 
+### Important
+This project dependent on react-ace. But there is a bug and a feature have not been merged to the original repository. This project can be built without error but it will raise error when run. 
+
 > npm install // install dependencies
 
 > npm run watch // you can open localhost:8080 to try it