URL shortener microservice

I created this app as a requirement for my freeCodeCamp APIs and Microservices Certification, using Node.js, Express, Mongoose, and a free MongoDB Atlas database. The front end API test on the main page also uses Bootstrap, jQuery, and highlight.js. The API fulfills the following user stories:

1. I can POST a URL to [project_url]/api/shorturl/new and I will receive a shortened URL in the JSON response.
   • Example: {"original_url": "www.google.com", "short_url": 1}
2. If I pass an invalid URL that doesn't follow the http(s)://www.example.com(/more/routes) format, the JSON response will contain an error like {"error": "invalid URL"}.
   • HINT: to be sure that the submitted url points to a valid site you can use the function dns.lookup(host, cb) from the dns core module.
3. When I visit the shortened URL, it will redirect me to my original link.