hub/auth: note about how to setup SSO authentication
hub/auth: note about how to setup SSO authentication

tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc