title: How to create a Collection of References in Firebase Firestore DB?
body: <p>Im looking to have a document, which contains a collection of references to other documents.  Like a <code>Project</code> that has a collection of <code>Users</code>, but the entries are <code>Reference</code> types to users from the top level <code>Users</code> collection.</p>
  
  <p>I can't see a way of adding a <code>Reference</code> type to a Collection, It looks like you must create a <code>Document</code> first and then have a field in that doc that is the reference to the user doc - but that is just adding extra work.</p>
  
  <p>When getting the collection data, you will have to first get the Document in the collection, and then using the field for the reference get the User Document.</p>
  
  <p>It would be far simpler to have a nested array of values.</p>
  
  <p>What is the best way to store a collection of references ?</p>