title: How can I set up userpool's preferred_username as sign in option via Amplify CLI?
body: <p>I am using Amplify CLI to create formation stack for Cognito Userpool.</p>
  <p>After <code>amplify add auth</code>I go through a setup process where one of the options is:</p>
  <pre><code>How do you want users to be able to sign in? Username 
  </code></pre>
  <p>However, after <code>amplify push</code> and checking userpool in AWS Console I see more options:</p>
  <p><a href="https://i.stack.imgur.com/CSnqi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CSnqi.png" alt="enter image description here" /></a></p>
  <p>Additionally to username I can choose &quot;Sign in with email&quot;, &quot;Sign in with verified phone number&quot;, &quot;Sign in with preferred username&quot;</p>
  <p>How these options can be chosen via Amplify CLI?</p>