Added Brunch build tool to the docs (#9074)

* Added Brunch build tool to the docs

* Improved grammar

* product build -> production build

(cherry picked from commit 0bedd0697a)

docs/docs/installation.md

@@ -99,6 +99,10 @@ By default, React includes many helpful warnings. These warnings are very useful
 
 If you use [Create React App](https://github.com/facebookincubator/create-react-app), `npm run build` will create an optimized build of your app in the `build` folder.
 
+#### Brunch
+
+To create an optimized production build with Brunch, just add the `-p` flag to the build command. See the [Brunch docs](http://brunch.io/docs/commands) for more details.
+
 #### Webpack
 
 Include both `DefinePlugin` and `UglifyJsPlugin` into your production Webpack configuration as described in [this guide](https://webpack.js.org/guides/production-build/).

docs/docs/optimizing-performance.md

@@ -13,6 +13,7 @@ If you're benchmarking or experiencing performance problems in your React apps,
 
 * For Create React App, you need to run `npm run build` and follow the instructions.
 * For single-file builds, we offer production-ready `.min.js` versions.
+* For Brunch, you need to add the `-p` flag to the `build` command.
 * For Browserify, you need to run it with `NODE_ENV=production`.
 * For Webpack, you need to add this to plugins in your production config: