title: oauth2-server and silex with user authentification
body: <p>I am new in Silex PHP framework and OAuth2, I could implement oauth2 server but there is no user authentication, I mean when user press authorize button it redirects directly authorization page where system will ask user allows this app or not, but without any user authentication I couldn't implement there sign in function. Is there anybody implement oauth2 and silex php framework together. Please someone can it would be very good thanks in advance!</p>