Refactor webpack config #358

// all resolves and common plugins registered in common
webpack.common.js
// other builds uses webpack-merge to merge common and extend with custom
webpack.dev.js
webpack.prod.js
webpack.test.js

const path = require('path');
const merge = require('webpack-merge');
const UglifyJSPlugin = require('uglifyjs-webpack-plugin');
const common = require('./webpack.common.js');
module.exports = merge(common, {
 devtool: 'source-map',
 entry: './src/index.js',
 output: {
 filename: 'app.min.js',
 path: path.resolve(__dirname, 'dist')
 },
 plugins: [
 new UglifyJSPlugin({
 sourceMap: true
 })
 ]
});