'nodemon'不被识别为内部或外部命令，可操作程序或批处理文件

我正在尝试全局安装nodemon，但我收到的警告如附图中所述。可能是因为警告，我无法运行nodemon。我的package.json

  {
   "name": "learn",
   "version": "1.0.0",
   "description": "",
   "main": "server.js",
   "scripts": {
   "test": "echo \"Error: no test specified\" && exit 1",
   "start": "node server.js"
  },
   "author": "himanshu",
   "license": "ISC",
   "dependencies": {
   "bcrypt-nodejs": "0.0.3",
   "body-parser": "^1.17.2",
   "express": "^4.15.4",
   "mongoose": "^4.11.7",
   "morgan": "^1.8.2"
  }
 }

我已将C:\Users\username\AppData\Roaming\npm添加到我的系统的环境变量中，它解决了我的问题。