title: Push Notifications with Firebase and OneSignal
body: <p>I'm looking for some guidance. </p>
  
  <p>I'm using Firebase as the backend server for an app I'm building and I would like to alert users when somebody has either liked or disliked some content the user generated. </p>
  
  <p>I understand that Firebase offers cloud messaging through which I can target very specific users and send updates to them; I have implemented that functionality. However, I would like to send updates based on changes in the database, and, as far as I understand, FCM is not built for this purpose. </p>
  
  <p>I have come across OneSignal and it seems promising. Has anybody implemented this with Firebase and could it do what I'm looking for?</p>
  
  <p>Thanks!</p>