OmniAuth
OmniAuth is a flexible authentication system utilizing Rack middleware
...In order to use OmniAuth in your applications, you will need to leverage one or more strategies. These strategies are generally released individually as RubyGems, and you can see a community-maintained list on the wiki for this project. One strategy, called Developer, is included with OmniAuth and provides a completely insecure, non-production-usable strategy that directly prompts a user for authentication information and then passes it straight through. You can use it as a placeholder when you start development and easily swap in other strategies later.