fixed migrating to create react app doc

issue: gaearon#595
reference: https://github.com/wangsongiam/create-react-with-hot-loader.git

docs/README.md

@@ -147,7 +147,7 @@ Hot reloading code is just one line in the beginning and one line in the end of
 * Run `npm run eject`
 * Install React Hot Loader (`npm install --save-dev react-hot-loader@next`)
 * In `config/webpack.config.dev.js`:
-  1. Add `'react-hot-loader/patch'` to entry array (anywhere before `paths.appIndexJs`). It should now look like (excluding comments):
+  Add `'react-hot-loader/patch'` to entry array (anywhere before `paths.appIndexJs`). It should now look like (excluding comments):
   ```js
     entry: [
        'react-hot-loader/patch',
@@ -156,25 +156,28 @@ Hot reloading code is just one line in the beginning and one line in the end of
        paths.appIndexJs
     ]
   ```
+* Add `AppContainer` to `src/index.js`:
+```js
+import { AppContainer } from 'react-hot-loader'
 
-  2. Add `'react-hot-loader/babel'` to Babel loader configuration. The loader should now look like:
-  ```js
-    {
-       test: /\.(js|jsx)$/,
-       include: paths.appSrc,
-       loader: 'babel',
-       query: {
-         cacheDirectory: findCacheDir({
-           name: 'react-scripts'
-         }),
-         plugins: [
-           'react-hot-loader/babel'
-         ]
-       }
-    }
-  ```
+function render(Component) {
+  ReactDOM.render(
+    <AppContainer>
+      <Component />
+    </AppContainer>,
+    document.getElementById('root')
+  )
+}
+
+render(App)
 
-* Add `AppContainer` to `src/index.js` (see `AppContainer` section in [Migration to 3.0 above](https://github.com/gaearon/react-hot-loader/blob/next-docs/docs/README.md#migration-to-30))
+if (module.hot) {
+  module.hot.accept('./App', () => {
+    render(App)
+  })
+}
+
+```
 
 ## TypeScript