Added live-server

Added start script
Add short "How to run" in readme

package.json

@@ -4,7 +4,8 @@
   "description": "A Phaser 3 Project Template",
   "main": "src/index.js",
   "scripts": {
-    "build": "webpack"
+    "build": "webpack",
+    "start": "npm run build && node_modules/.bin/live-server --port=8000"
   },
   "repository": {
     "type": "git",
@@ -18,6 +19,7 @@
   },
   "homepage": "https://github.com/photonstorm/phaser3-project-template#readme",
   "devDependencies": {
+    "live-server": "^1.2.0",
     "phaser": "^3.0.0-alpha.2",
     "webpack": "^3.4.1"
   }