active record association: has only one.

Hello guys!
I'm new on RoR. I'm testing an application for married person using this
source
https://github.com/serv/Ruby-on-Rails-Tutorial-by-Michael-Hartl--v3.2-
The goal is:
- A sign-in person can only get only one follower ( his wife or husband)

Where should i modified this app for this features?
Thanks for your help!

Go to http://guides.rubyonrails.org/association_basics.html and you’ll find what you need.

As a side note, you should bookmark http://guides.rubyonrails.org/ and get familiar with its’ contents.

Rick