Improve documentation addressed in #71 (#123)

* Improve documentation

* Elaborate wordings

* Remove sponsors

README.md

@@ -5,6 +5,8 @@
 
 A mock store for testing your redux async action creators and middleware. The mock store will create an array of dispatched actions which serve as an action log for tests.
 
+Please note that this library is designed to test the action-related logic, not the reducer-related one. In other words, it does not update Redux store. If you want a complex test combining action and reducer together, take a look at other libraries (e.g., [redux-actions-assertions](https://github.com/redux-things/redux-actions-assertions)). Refer issue [#71](https://github.com/arnaudbenard/redux-mock-store/issues/71) for more detail.
+
 ## Install
 
 ```
@@ -136,4 +138,4 @@ The following versions are exposed by redux-mock-store from the `package.json`:
 
 ## License
 
-MIT
+The MIT License