CORS issue1#:
    Besides * is too permissive and would defeat use of credentials. So
    add localhost:3000 or localhost:8000 to the allow origin header.
CORS issue#2
    if disable the credentials, the cookies will not send to server
    that will make server cannot get current user easily
correct the error message
remove the debug code block
add the angular-cookie to help take care the cookie set/get/delete stuff
fix the typo
add cookie write action, just on debug phase
add group join service
add the model to template
start the TDD