Add warning

Author: georgeboot

README.md

@@ -1,5 +1,12 @@
 # laravel-echo-api-gateway
 
+## !! Work in progress !!
+
+Note that this package is a work in progress. As soon as version 0.1 will be tagged, it will be usable for testing
+purposes. As soon as version 1.0 gets released, it should be usable for production purposes.
+
+## About
+
 This package enables you to use API Gateway‘s Websockets as a driver for [Laravel Echo](https://github.com/laravel/echo)
 , so you don’t have to use services like Pusher or Socket.io.