lib/formula.rb
def formula_form_for(record_or_name_or_array, *args, &proc)
      options = args.extract_options!
      options[:builder] ||= @@builder
      form_for(record_or_name_or_array, *(args << options), &proc)
    end
def formula_form_for(record_or_name_or_array, *args, &proc)
      options = args.extract_options!
      options[:builder] ||= @@builder
      form_for(record_or_name_or_array, *(args << options), &proc)
    end
Generates a wrapper around form_for with :builder set to FormulaFormBuilder.

 Supports:

 * formula_form_for(@user)

 Equivalent:

 * form_for(@user, :builder => Formula::FormulaFormBuilder))

 Usage:

   <% formula_form_for(@user) do |f| %>
     <%= f.input :email %>
     <%= f.input :password %>
   <% end %>