selector.rb

Capybara.add_selector :record do
  xpath { |record| XPath.css("#" + ActionController::RecordIdentifier.dom_id(record)) }
  match { |record| record.is_a?(ActiveRecord::Base) }
end

use_it_like_this.rb

post = Post.first

find(post).click_link("Hello")

within post do
  fill_in("What's going on here", :with => "Holy shit this works??")
  click_button("Yes")
end