title: Firebase "refer and earn" or invites using Reward Referals?
body: <p>I want to implement "refer and earn" concept using 
  <a href="https://firebase.google.com/docs/dynamic-links/use-cases/rewarded-referral" rel="nofollow noreferrer">https://firebase.google.com/docs/dynamic-links/use-cases/rewarded-referral</a> in my application.</p>
  
  <p>When I'm creating dynamic links with user id </p>
  
  <pre><code>FirebaseUser user = mAuth.getInstance().getCurrentUser(); 
  </code></pre>
  
  <p>get current user always returns null.</p>
  
  <p>My questions are:</p>
  
  <ol>
  <li><p>If I want to implement "refer and earn" using dynamic links, I have to make user sign up or sign in with Firebase login system (Firebase email login, fb login...e.t.c). </p></li>
  <li><p>If I have my own database for signup and I'm storing credentials and validating user from  server. So I'm not using the firebase login system. Is it still possible to implement "refer and earn" using firebase?</p></li>
  <li><p>How to track the people who installed or not and how should I give him rewards.</p></li>
  </ol>
  
  <p>Please give me some example or sample links if any one implemented "refer and earn"</p>