title: Firebase on change event. How to know who changed data?
body: <p>On child_changed event I receive changed data but don know who changed it, is there any possibility to get this information ?</p>
  
  <pre><code>database.ref('projects').on('child_changed', snapshot =&gt; {
      // something like
      // if (snapshot.userID === currentUserId)
      // if current user did changes
      //    do nothing    
      // } else {
      //    update UI
      // }
  })
  </code></pre>