fix(doc): add reference to winglang module system in the README.md (#118

)

README.md

@@ -71,7 +71,10 @@ And then:
 bring my-awesome-lib
 ```
 
+## Writing Wing Libraries
+
+See [docs](https://www.winglang.io/docs/libraries#creating-a-wing-library).
 ## License
 
 This repository is licensed under the [MIT License](./LICENSE), unless otherwise specified in a
-library directory.
+library directory.