title: Create a reference to a Cloud Storage document in Firestore
body: <p>I am using Firebase, and I try to create a reference to a Cloud Storage document in a Firestore document.</p>
  <p>In my Console &gt; Storage, I have a folder <code>discovery</code> that contains a file <code>heart.png</code>.</p>
  <p>In my Firestore document, I have a <code>reference</code> field named <code>src</code>. I have tried to fill it with:</p>
  <ul>
  <li><code>discovery/heart.png</code></li>
  <li><code>gs://&lt;NAME&gt;.appspot.com/discovery/heart.png</code></li>
  <li><code>&lt;NAME&gt;.appspot.com/discovery/heart.png</code></li>
  </ul>
  <p>but it doesn't work...
  When I try to get the image like this <code>src.get().then(snap =&gt; console.log(snap.data()))</code> the result is always <code>undefined</code>.</p>
  <p>Does the reference fields are only designed for the database's documents (not Storage ones)?
  I can't find how to reference a Storage file in a Firestore document neither on the documentation nor on Google.</p>
  <p>Could someone help me, please? :)
  Thanks a lot!</p>