title: How can one allow only specific email accounts to login into your android app?
body: <p>I'm trying to make an app for my college and only want email ending with specific endings to register so that no other person say using Hotmail.com or gmail.com or any other can't register on my app. 
  Also I want to make it dynamic so in future If I have to add a few more domains i dont have to update the app whole together. I was planning to use firebase for the project but am open to use anything else also for authentication if that solves my problem. </p>