define SendOnlineMsg
define user's routing_key
define sending and receive normal message
define send quit msg in client
fixed msg without ack
define handle_offline_msg
refactory the frame of the code
refactory delete client_list
define specify destination user
handle client_list
define settings
add settings file
fixed queue bug and make msg durable
add checking invalid user id
define interface for user
modify usage of server
modify README