Add start script

package.json

@@ -11,5 +11,8 @@
     "multer": "^1.4.5-lts.1",
     "pdf-to-printer": "^5.6.0",
     "unix-print": "^1.3.2"
+  },
+  "scripts": {
+    "start": "node index.js"
   }
 }