title: Firebase with Google Cloud Messaging in Android Java
body: <p>Is there any possibility to implement GCM with Firebase Server...?<br>
  if it is then how we can do it.?<br>
  Example i have a chat application in which the back-end server is firebase only no other services and also the authentication system of firebase is implemented then how we send the notification to specific user to notify that there is some msgs from other users.</p>