chore: webpack upgrade (#98)

* upgraded to webpack 4.x

* updated webpack

webpack.dev.js

@@ -0,0 +1,80 @@
+const webpack = require('webpack')
+const path = require('path')
+const HtmlWebpackPlugin = require('html-webpack-plugin');
+
+module.exports = {
+	mode: 'development',
+
+	module: {
+		rules: [{
+			include: [
+				path.resolve(__dirname, 'src'),
+				path.resolve(__dirname, 'examples')
+			],
+			test: /\.js$/
+		}, {
+			test: /\.(js)$/,
+			exclude: /node_modules/,
+			use: ['babel-loader']
+		}, {
+			test: /\.css$/,
+			use: [{
+				loader: 'style-loader',
+				options: {
+					sourceMap: true
+				}
+			}, {
+				loader: 'css-loader'
+			}]
+		}]
+	},
+
+	resolve: {
+		extensions: ['.js'],
+		alias: {
+			'CodeMirror':	path.join(__dirname, 'node_modules', 'codemirror'),
+			'jQuery':		path.join(__dirname, 'node_modules', 'jquery')
+		}
+	},
+
+	plugins: [
+		new HtmlWebpackPlugin({
+			template: 'examples/app.html',
+			filename: 'mergely.html'
+		}),
+		new webpack.ProvidePlugin({
+			$: 'jquery',
+			jQuery: 'jquery'
+		}),
+		new webpack.ProvidePlugin({
+			CodeMirror: 'codemirror'
+		})
+	],
+
+	entry: {
+		app: [
+			'./examples/app',
+			'./src/mergely',
+		]
+	},
+
+	output: {
+		filename: 'mergely.js',
+	},
+
+	optimization: {
+		splitChunks: {
+			cacheGroups: {
+				vendors: {
+					priority: -10,
+					test: /[\\/]node_modules[\\/]/
+				}
+			},
+
+			chunks: 'async',
+			minChunks: 1,
+			minSize: 30000,
+			name: true
+		}
+	}
+}