Rails3 own scaffold generator

Question

./script/rails g generator admin

class AdminGenerator < Rails::Generators::NamedBase
  def self.source_root
    @source_root ||= File.expand_path('../templates', __FILE__)
  end

  def manifest
    #I know I can copy my template files with the 'template' method
    #How I can generate a migration, and a model here ?
  end
end