authentication.rb

# app/models/user/

class User
  
  include Authentication
  include Authentication::ByPassword
  include Authentication::ByCookieToken
  
  def self.authenticate(login, password)
    unless login.blank? or password.blank?
      u = find_by_username_or_email(login)
      u && u.authenticated?(password) ? u : nil
    end
  end

end

concerns.rb

# app/config/initializers/
# Credit to technoweenie:

class << ActiveRecord::Base
  def concerned_with(*concerns)
    concerns.each do |concern|
      require_dependency "#{name.underscore}/#{concern}"
    end
  end
end

class << ActionMailer::Base
  def concerned_with(*concerns)
    concerns.each do |concern|
      require_dependency "#{name.underscore}/#{concern}"
    end
  end
end

user.rb

# app/models/

class User < ActiveRecord::Base

  # Macro to aid in refactoring large Models into concerns
  concerned_with :activation,
                  :authentication,
                  :recent_projects,
                  :roles,
                  :rss,
                  :scopes
end