Add reference to <Async>

Author: ghengeveld

README.md

@@ -18,6 +18,8 @@ any messages or errors it sends, as well as the `postMessage` handler.
 - Provides `postMessage` to send messages to the Web Worker
 - Accepts `onMessage` and `onError` callbacks
 
+> This package was modeled after [`<Async>`](https://github.com/ghengeveld/react-webworker) which helps you deal with Promises in React.
+
 ## Install
 
 ```