title: Command insert requires authentication
body: <p>I have tried this</p>
  
  <pre><code>mongoose.connect('mongodb://localhost/ninjago', { useNewUrlParser: true });  
  </code></pre>
  
  <p>to connect mongodb on nodejs and working fine.</p>
  
  <p>But when i try to create data, it gives this error </p>
  
  <blockquote>
    <p>"(node:18194) UnhandledPromiseRejectionWarning: MongoError: command insert requires authentication"  </p>
  </blockquote>
  
  <p>can anyone help me out? i am using ubuntu 18.04.</p>