Where is access control managed for Cloud - Single Organization Authentication / Office 365?

I am creating a new web app in visual strudio 2013 and it's very cool that I can pick my Office 365 deployment for the authentication option, but where do I manage what users have access to the app?  Can't seem to locate that documentation.

http://www.asp.net/visual-studio/overview/2013/creating-web-projects-in-visual-studio#orgauthoptions