Railsers:
As usual for a product written very rapidly, most of its documentation assumes someone else told you something critical.
For example, the file form_helper.rb tempts me with this documentation:
# <% form_for :person, @person, :url => { :action => "update" }, :builder => LabellingFormBuilder do |f| %>
That's beautiful. Now what do I require() into my controller.rb file to get that LabellingFormBuilder identifier? Poking around with 'form_helper', 'helper', etc doesn't do it.