gistfile1.rb

class Relation < ActiveRecord::Base
  belongs_to :feed
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :relations
  has_many :feeds, through: :relations, uniq: true
end

class Feed < ActiveRecord::Base
  has_many :relations
  has_many :users, through: :relations, uniq: true
  has_many :entries
end

class Entry < ActiveRecord::Base
  has_one :feed
end