Karma is a Web service provider for tracking "karma" points of users who are distributed across several separate Web applications. It is useful for when sites want to allow community contributions to content, but certain higher types of content should only be able to be submitted by people who have demonstrated the ability to contribute value at lower levels. The vision is to create a generic karma service where a central server instance provides its services to several related Web applications. Those applications are the clients of the karma server instance. They can quickly and securely submit and retrieve karma for their users.
Roles UI is a graphic interface library for Ruby on Rails which provides the ability to manage roles and permissions in realtime for applications which use Cancan. It is a Rails engine, so it has its own namespace. You can reach Roles UI in /roles_ui. Roles UI consist of two main entities, Role and Permission. Each Role may have a permission set. Roles belongs to users. Roles UI extends your User model so you don't need to create this association. By default, Roles UI is configured to work with the User model.