spring security defining user registration with ROLE_USER

hello i am making a project in spring mvc 4 with hibernate and spring security. In this project i have 3 roles ROLE_USER ROLE_COMPANY and ROLE_ADMIN. User will register like regular registration site, but I am confused on how to save a new user in database through registration process, that how to save the new user n database defined by spring security and how to fetch that information using hibernate. Thank you.