riffing-artifact.rb

class User
  belongs_to :timeline
end

class User::Timeline
  has_many :items
end

class User::Timeline::Item
  belongs_to :timeline
end

class User::TimelinesController
  def show
    @items = Current.user.timeline.items.order(:created_at)
  end
end

# app/views/user/timelines/show.html.erb
@items.each do |item|
  if Current.user.favorite?(item)
    button_to unfavorite_item_path(item), method: :delete
  else
    button_to favorite_item_path(item)
  end
end