It's really easy to create a many-to-many relationship that can be assigned through checkboxes. Check it out! Let's say you have Users and Groups. A User can belong to a Group and a Group can have many Users – we call this a Membership, like so (migrations omitted for brevity): app/models/user.rb class User < ActiveRecord::Base has_many :memberships, :dependent => :destroy has_many :groups, :throu
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