arrange npm scripts

package.json

@@ -4,8 +4,9 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "build": "webpack -w",
-    "start:dev": "webpack-dev-server"
+    "build": "node_modules/.bin/webpack",
+    "build:watch": "node_modules/.bin/webpack -w",
+    "start:dev": "node_modules/.bin/webpack-dev-server"
   },
   "author": "",
   "license": "ISC",