Rails User Accounts Data Merge

I have a live Ruby on Rails web application running on Ubuntu (with Passenger + Nginx).
There are two user accounts in the system that need to be merged, so that one user can access all the data of the other.

I’m not fully sure how the user relationships are structured in the database, so I need someone experienced with Rails to:

- Check how user data is linked across the app
- Safely merge one user’s data into another
- Make sure everything still works correctly after the merge

I’ll walk you through how the system functions and provide SSH access to the server.

Requirements:

- Solid experience with Ruby on Rails and database structure analysis
- Able to work directly on a production environment (safely)
- Comfortable inspecting associations and Devise setup