Shared configuration documentation

README.md

@@ -107,6 +107,34 @@ config
 module.exports = config.getConfig();
 ```
 
+Having shared configurations is also simple. Just export the configuration
+and call `.getConfig()` prior to passing to Webpack.
+
+```js
+// webpack.core.js
+const Config = require('webpack-chain');
+const config = new Config();
+
+// Make configuration shared across targets
+// ...
+
+module.exports = config;
+
+// webpack.dev.js
+const config = require('./webpack.core');
+
+// Dev-specific configuration
+// ...
+module.exports = config.getConfig();
+
+// webpack.prod.js
+const config = require('./webpack.core');
+
+// Production-specific configuration
+// ...
+module.exports = config.getConfig();
+```
+
 ## API
 
 ### Config