chore(package): Add npm run script for webpack

Make life simpler

Change-Type: patch

package.json

@@ -24,6 +24,8 @@
     "configure": "node-gyp configure",
     "build": "node-gyp build",
     "install": "node-gyp rebuild",
+    "webpack": "webpack",
+    "watch": "webpack --watch",
     "concourse-build-electron": "make webpack",
     "concourse-test": "npm test",
     "concourse-test-electron": "npm test",

webpack.config.js

@@ -67,7 +67,8 @@ module.exports = {
         use: {
           loader: 'babel-loader',
           options: {
-            presets: [ 'react', 'env', 'stage-0' ]
+            presets: [ 'react', 'env', 'stage-0' ],
+            cacheDirectory: true
           }
         }
       },