Removed invalid config. Default behavior is the same.

Author: coryhouse

webpack.config.js

@@ -20,7 +20,7 @@ var getPlugins = function(env) {
     case 'production':
       plugins.push(new ExtractTextPlugin('styles.css'));
       plugins.push(new webpack.optimize.DedupePlugin());
-      plugins.push(new webpack.optimize.UglifyJsPlugin({minimize: true, sourceMap: true}));
+      plugins.push(new webpack.optimize.UglifyJsPlugin());
       break;
     case 'development':
       plugins.push(new webpack.HotModuleReplacementPlugin());