Both, active_admin
and rails_admin
provide convenient ways to access and manage your database from a GUI interface. How you present that data is totally upto you. If by admin panel, you mean an admin dashboard like this, neither of them does that:
Admin dashboards are very application specific and depends on what type of data you want to display. active_admin and rails_admin will help you get data from your application but it's then upto you to display that data in whatever format/interface you want.