Help me change a user on my website to "admin" class inside PostgreSQL database

I've got a website running. It creates users when they register on the front-end. By default, the PostgreSQL database creates all new users with a class of "user" inside the database. I need to change MY "user class" to "admin" so that I can access the admin sections of the website. The database is already built, and I just simply need help accessing the database, and changing the "user class" of my username from the "user" class, to the "admin" class. This should only take like 10 minutes or less for someone who knows how to use PostgreSQL. This should be an easy, quick job. If done properly I will be able to access the Admin section of the website. Thank you.