Question

I’m trying to figure out how to set up the relationship/association for a Document model for my rails project. I have a User model and Users can friend each another (friendship model).

Now I want users to be able to invite (give access to) CERTAIN friends to modify and edit these documents similar to Google Docs.

This is my current approach to this problem:

Create a new relationship model called “group”, essentially a subset of friends. Document belongs to a user and document belongs to a group. Users can then invite their friends into these group relationships and documents can be accessed/modified through these groups.

Therefore, User has many groups and group belongs to many users.

My question:

1. Is there a better approach to this problem?

Answer 1

You might consider a “Membership” join table. So:

Group >- Membership -< User

…since you requirement is some users will have abilities others wont (editing). There are all sorts of options from there, for example STI which would give you:

class Membership < ActiveRecord::Base
  ...general membership functions
end

class Editor < Membership
   ...editor specific code...
end

class Reviewer < Membership
   ...reviewer specific code...
end

And a controller class something like

class MembershipController
  def create invitation
    if invitation.for_editor?
      # assuming invitation has one group, and group_memberships method that returns group.memberships
      invitation.group_memberships.create! user: current_user
    else
      invitation.group_memberships.create! user: current_user
    end
  end
end

As an example, depending on your opinion of STI.

https://github.com/scambra/devise_invitable

might have more ideas.