Just a quick and dirty email collector running on rails 6
/users/new
register a new user
Make an admin on the command line
rails c
u = User.find(1) # Use any rails find method
u.admin=true
u.save
/logout
Log out of the session
/login
Create a new session
Now you'll have an admin menu that you can use to navigate around the admin portions of the app, checking the list of all collected emails and the list of all users.