title: How do i only allow specific email to login into my page
body: <p>There are two sides, Admin and Users. I am using the same database in firebase for both Users and Admin. It means that Users that are registered in my firebase authentication, can login to Admin webpage. How do i allow only specific admin's email to login into the Admin page. </p>
  
  <p>For example:
  Admin has an email of admin@admin.com</p>
  
  <p>User has various email like 123@gmail.com, 222@gmail.com and etc.</p>
  
  <p>What i want is only to allow admin@admin.com to be able to login into the Admin page but restrict login for User emails to login to the Admin page. </p>