gistfile1.rb

require 'bcrypt'

module Ark
  module Mixins
    module BCryptUser
      def self.included(base)
        base.class_eval do
          attr_accessor :password, :password_confirmation

          before_save :encrypt_password

          field :crypted_password, :type => String, :length => 60

          validates_presence_of :password, :password_confirmation, :if => proc { self.password_required? }
          validates_confirmation_of :password, :if => proc { self.password_required? }

          extend Ark::Mixins::BCryptUser::ClassMethods
          include Ark::Mixins::BCryptUser::InstanceMethods
        end
      end

      module ClassMethods
        def authenticate(username, password)
          puts username
          puts password
          u = User.find(username)
          u && u.authenticated?(password) ? u : nil
        end
      end

      module InstanceMethods
        def authenticated?(password)
          bcrypt_password == password
        end

        def bcrypt_password
          @bcrypt_password ||=  BCrypt::Password.new(crypted_password)
        end

        def password_required?
          crypted_password.blank? || !password.blank?
        end

        def encrypt_password
          return if password.blank?
          cost = BCrypt::Engine::DEFAULT_COST
          self.crypted_password = BCrypt::Password.create(password, :cost => cost)
        end
      end
    end
  end
end

gistfile2.rb

Warden::Strategies.add(:basic) do
  def valid?
    params["user"]["username"] && params["user"]["password"]
  end

  def authenticate!
    u = User.authenticate(params["user"]["username"], params["user"]["password"])
    u.nil? ? fail!("Could not log in") : success!(u)
  end
end