package.json in tang-0.1.0

- old
+ new

@@ -6,7 +6,10 @@
   "dependencies": {
     "@rails/webpacker": "^5.2.1"
   },
   "devDependencies": {
     "webpack-dev-server": "^3.11.0"
+  },
+  "scripts": {
+    "build": "RAILS_ENV=development NODE_ENV=development bin/webpack --watch"
   }
 }