This application uses Ruby on Rails, Devise, and Doorkeeper to provide a lightweight service for OAuth clients. It is optimized for free deployment on Heroku but can be set up in any environment suitable for hosting Rails applications.
If you have an account on Heroku, you can use the button provided here to launch your own free instance of the application:
As an additional, optional step in deploying your instance to Heroku, you can attach the SendGrid add-on so that the application can send email to users, namely in the case that a user requests a password reset. To do this, click Manage App after deployment has completed, then click the Resources tab. In the search box for Add-ons, look up SendGrid. The free tier of the add-on will work with this application, but Heroku will still require that you add a credit card number to your account in order to attach it to your application. To do so, click on the search result for SendGrid and then click Provision.
To enable a client application to manage user logins through your provider, navigate to your-application-url/oauth/applications and click New Application. Enter a name and one or more callback URIs in the corresponding fields, then click Submit to save.
See the documentation for Devise and Doorkeeper for further functionality and view customization that can be enabled through these libraries.
See the Digital Ocean guide to using the one-click Ruby on Rails installer in order to provision a droplet suitable for installing and deploying an instance of this application.