How can I add Adminer to my Ruby on Rails application with PostgreSQL?

I am new to ruby on rails. This question may be simple. I have been trying to add an adminer folder on the app on ruby on rails application. My database is PostgreSQL. I want to manage my database on the browser using adminer.

I wish someone could help me get an answer as to whether it's possible to add admins to a Ruby on Rails app. If you can add admins, please briefly explain how to do so. Thank you in advance.