title: Firestore get array from collection with id's to use in Polymer dom-repeat
body: <p>im trying to use Firestore with Polymer, I obtain an array to send it to polymer in a dom-repeat like this:</p>
  
  <pre><code>    var query=db.collection("operaciones");
      db.collection("operaciones")              
      .onSnapshot((querySnapshot) =&gt; {
      querySnapshot.forEach(function(doc) {
      });
          that.operacionesPorCliente=Array.from(querySnapshot.docs.map(doc=&gt;doc.data()));
      });
      console.log (that.operacionesPorCliente);   // this works but the ID doesnt exist here....
      }
  </code></pre>
  
  <p>that works but that array doesnt contain the id from firestore, the problem is that I need that ID to update the data :( but it isn't in the array</p>
  
  <p>Hope I explain my self, any help?</p>