Autologin in development strategy for devise

devise.rb

# Reference(s):
# - http://kyan.com/blog/2013/10/11/devise-authentication-strategies
# - https://github.com/plataformatec/devise/blob/master/lib/devise/strategies/database_authenticatable.rb
module Devise
  module Strategies
    class Autologin < Authenticatable
      def authenticate!
        user = User.first
        user ? success!(user) : fail!("No administrator account available")
      end

      def valid?
        Rails.env.development?
      end
    end
  end
end

# config/initializers/devise.rb
Devise.setup do |config|
  # ...
  config.warden do |manager|
    manager.strategies.add(:autologin, Devise::Strategies::Autologin)   
    manager.default_strategies(:scope => :user).unshift :autologin
  end
end