If you’ve built many Rails application, odds are high you’ve encountered the Devise gem. Devise provides several standard features we have all come to expect from modern web applications, such as logging in, securely storing passwords in a database, user tracking, and automatic session expiration. However, when you must authenticate with a new service or your company has its own authentication mechanisms (for example, an SSO portal) do avoid the temptation to design your own authentication service. Instead, follow the steps in this guide and you’ll be able to use Devise and Warden with any form of authentication.

http://www.ldstudios.co/blog/2016/06/15/how-to-create-custom-authentication-strategies-with-devise-and-warden.html