added note about Passenger compatibility
added note about Passenger compatibility

adamdruppe/rubycas-server,chowells79/rubycas-server,jay3126/ruby_cas_server,identification-io/rubycas-server,intinno/ruby-cas-server,DiegoSalazar/ROR-RubyCAS-Server,geo767/rubycas-server,geo767/rubycas-server,intinno/ruby-cas-server,acsellers/cas,infoman/rubycas-server,adamdruppe/rubycas-server,rubycas/rubycas-server,Windermere/rubycas-server,DiegoSalazar/ROR-RubyCAS-Server,Windermere/rubycas-server,infoman/rubycas-server,Windermere/rubycas-server,rubycas/rubycas-server,identification-io/rubycas-server,chowells79/rubycas-server,identification-io/rubycas-server,chowells79/rubycas-server,acsellers/cas,rubycas/rubycas-server,adamdruppe/rubycas-server,jay3126/ruby_cas_server,infoman/rubycas-server,geo767/rubycas-server