Readme: installation, npm badge

Author: danburzo

README.md

@@ -1,11 +1,24 @@
 # rollup-plugin-css-bundle
 
-A [Rollup](https://github.com/rollup/rollup) plugin whose sole purpose is to collect all the CSS files you import into your project and bundle them into a single glorious CSS file. Refreshingly, it preserves the order in which the CSS files are imported. Soberingly, it does not generate source maps. 
+A [Rollup](https://github.com/rollup/rollup) plugin whose sole purpose is to collect all the CSS files you import into your project and bundle them into a single glorious CSS file. Refreshingly, it preserves the order in which the CSS files are imported. Soberingly, it does not generate source maps.
+
+## Installation
+
+<a href="https://www.npmjs.org/package/rollup-plugin-css-bundle"><img src="https://img.shields.io/npm/v/rollup-plugin-css-bundle.svg?style=flat" alt="npm version"></a>
+
+```bash
+# using npm
+npm install --save-dev rollup-plugin-css-bundle
+
+# using yarn
+yarn add --dev rollup-plugin-css-bundle
+```
 
 ## Usage
 
+In your **rollup.config.js** file:
+
 ```js
-// rollup.config.js
 import cssbundle from 'rollup-plugin-css-bundle';
 
 export default {
@@ -14,17 +27,15 @@ export default {
 		file: 'dist/index.js',
 		format: 'cjs'
 	},
-	plugins: [
-		cssbundle()
-	]
-}
+	plugins: [cssbundle()]
+};
 ```
 
-Like all well-behaved Rollup plugins, cssbundle supports the __include__ and __exclude__ options that filter the files on which the plugin should run.
+Like all well-behaved Rollup plugins, cssbundle supports the **include** and **exclude** options that filter the files on which the plugin should run.
 
-__output__: _String_ is an optional path for the extracted CSS; when ommitted, we use the bundle's file name to fashion a path for the bundled CSS.
+**output**: _String_ is an optional path for the extracted CSS; when ommitted, we use the bundle's file name to fashion a path for the bundled CSS.
 
-__transform__: _Function_ is available for processing the CSS, such as with [postcss](https://github.com/postcss/postcss). It receives a string containing the code to process as its only parameter, and should return the processed code. _Par exemple_:
+**transform**: _Function_ is available for processing the CSS, such as with [postcss](https://github.com/postcss/postcss). It receives a string containing the code to process as its only parameter, and should return the processed code. _Par exemple_:
 
 ```js
 // rollup.config.js