Not sure if many people are familiar with Scaffolding Extensions for Ruby, but I've looked through their docs, forums, and even the source code of the Heroku test site, and not found an answer.

I made a basic Sinatra app and followed right from the RDoc's instructions:

require 'scaffolding_extensions'
require 'sinatra/base'
class Thingy < Sinatra::Base
  scaffold_all_models
end

gives

undefined method 'scaffold_all_models' for Thingy:Class (NoMethodError)

and I know Scaffolding Extensions is loadable because I can successfully set some config variables in its classes.