Merge pull request #29 from lektor/feature/documentation

Webpack doc fixes

content/docs/guides/webpack/contents.lr

@@ -46,7 +46,7 @@ start is to create an almost empty file:
 Now we can `npm install` all the things we want:
 
 ```
-$ npm install --save-dev webpack babel-core node-sass babel-loader sass-loader css-loader url-loader style-loader file-loader
+$ npm install --save-dev webpack babel-core node-sass babel-loader sass-loader css-loader url-loader style-loader file-loader extract-text-webpack-plugin
 ```
 
 This will install webpack itself together with babel and sass as well as
@@ -77,8 +77,8 @@ var ExtractTextPlugin = require('extract-text-webpack-plugin');
 
 module.exports = {
   entry: {
-    app: './js/main.js',
-    styles: './scss/main.scss'
+    'app': './js/main.js',
+    'styles': './scss/main.scss'
   },
   output: {
     path: path.dirname(__dirname) + '/assets/static/gen',