Adding webpack dev server support.

package.json

@@ -13,8 +13,8 @@
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
     "build": "webpack --config webpack.dev.js",
-      "prod": "webpack --config webpack.prod.js",
-      "cypress:open": "cypress open"
+    "prod": "webpack --config webpack.prod.js",
+    "cypress:open": "cypress open"
   },
   "keywords": [],
   "author": "",
@@ -45,6 +45,7 @@
     "terser-webpack-plugin": "^2.3.5",
     "webpack": "^4.41.5",
     "webpack-cli": "^3.3.10",
+    "webpack-dev-server": "^3.11.0",
     "webpack-merge": "^4.2.2"
   },
   "dependencies": {