Add record to a has_and_belongs_to_many relationship

Question

I have two models, users and promotions. The idea is that a promotion can have many users, and a user can have many promotions.

class User < ActiveRecord::Bas         


        

Answer 1

This is also useful

User.promotion.build(attr = {})

so, promotion object saves, when you save User object.

And this is

User.promotion.create(attr = {})

create promotion you not need to save it or User model