Rack Middleware for websites that need to contain access to a group of ip addresses (a whitelist).
Outside these addresses, vistors are shown 403 Forbidden page.
in Gemfile
gem 'rack-ip-whitelist'
in config/application.rb
config.middleware.use Rack::IpWhiteList, %w(55.44.22.11 55.44.11.22) # array of whitelisted addresses%