How To See A Database On Heroku
You can connect directly to it using something like PGAdmin, look at the output of heroku config for your application to get your database URL which you can breakup to use in GUI tools.
How do I see the database for my heroku web app? 
I just want to verify if users are being registered, properly, etc.
I am using Flask-SQLAlchemy Python, if that makes a difference.