Topic: uninitialized constant Nifty::Generators::ScaffoldGenerator::ActiveRec

I am using the tutorial on railcast to implement omniauth facebook login on my ruby on rails project.

When I run the command "rails g nifty:scaffold authentication user_id:integer provider:string uid:string index create destroy" it creates create app/models/authentication.rb, test/unit/authentication_test.rb and test/fixtures/authentications.yml.

But however it shows this gems/nifty-generators-0.4.6/lib/generators/nifty/scaffold/scaffold_generator.rb:310:in `next_migration_number': uninitialized constant Nifty::Generators::ScaffoldGenerator::ActiveRecord (NameError)

When I run rake after it says rake aborted! Don't know how to build task 'db:migrate'

I have been stuck here for a while now, I would really appreciate if someone can help me out here.