How to add a new and separeted role:"feed"/plugin

Hello, I am very new in mastodon and even more in Rails, but I am looking for a way to add a new and separate frame in the user’s GUI, I would like something similar to the role: “feed”, to represent personalized content of the active user. Also, it may be to insert a Plugin that allows me to display information that I have stored in a parallel table on my mastodon server.

Thank you very much.