docs(README): improve package description (#60)

Author: skipjack

README.md

@@ -9,7 +9,7 @@
       src="https://cdn.rawgit.com/webpack/media/e7485eb2/logo/icon.svg">
   </a>
   <h1>Compression Plugin</h1>
-  <p>Compression plugin for Webpack.<p>
+  <p>Prepare compressed versions of assets to serve them with Content-Encoding.<p>
 </div>
 
 <h2 align="center">Install</h2>
@@ -94,4 +94,4 @@ Option Arguments for Zopfli (see [node-zopfli](https://github.com/pierreingleber
 [deps-url]: https://david-dm.org/webpack-contrib/compression-webpack-plugin
 
 [chat]: https://img.shields.io/badge/gitter-webpack%2Fwebpack-brightgreen.svg
-[chat-url]: https://gitter.im/webpack/webpack
+[chat-url]: https://gitter.im/webpack/webpack