title: How to get insert id after save to database in CodeIgniter 4
body: <p>I'm using Codeigniter 4. </p>
  
  <p>And inserting new data like this,</p>
  
  <pre><code>$data = [
          'username' =&gt; 'darth',
          'email'    =&gt; 'd.vader@theempire.com'
  ];
  
  $userModel-&gt;save($data);
  </code></pre>
  
  <p>Which is mentioned here: <a href="https://codeigniter.com/user_guide/models/model.html#saving-data" rel="noreferrer">CodeIgniter’s Model reference</a></p>
  
  <p>It's doing the insertion. 
  But I haven't found any reference about to get the inserted id after insertion.</p>
  
  <p>Please help! Thanks in advance. </p>