title: Retrieving a list of users who have registered using Firebase Auth
body: <p>I am making an android chat application using firebase. So far I have made a common group chat app. Now I want to make it an individual chat app, which will have a Users list and when we select a person from that list we can chat individually with him/her. However I am not able to get this Users list from Firebase. I have kept Google Sign in and Email sign in options in the Firebase Auth UI. Any help would be appreciated</p>