Add a note on cdnjs

Author: gaearon

README.md

@@ -11,11 +11,15 @@ Performant and flexible.
 
 ## Installation
 
+React Redux requires **React 0.14 or later.**
+
 ```
 npm install --save react-redux
 ```
 
-React Redux requires **React 0.14 or later.**
+This assumes that you’re using [npm](http://npmjs.com/) package manager with a module bundler like [Webpack](http://webpack.github.io) or [Browserify](http://browserify.org/) to consume [CommonJS modules](http://webpack.github.io/docs/commonjs.html).
+
+If you don’t yet use [npm](http://npmjs.com/) or a modern module bundler, and would rather prefer a single-file [UMD](https://github.com/umdjs/umd) build that makes `ReactRedux` available as a global object, you can grab a pre-built version from [cdnjs](https://cdnjs.com/libraries/react-redux). We *don’t* recommend this approach for any serious application, as most of the libraries complementary to Redux are only available on [npm](http://npmjs.com/).
 
 ## React Native