emacs's gnus setting

(setq user-mail-address "huzhili@gmail.com")
(setq user-full-name "ZhiLi Hu")
(load-library "smtpmail")
(load-library "nnimap")
(load-library "starttls")
(setq gnus-select-method '(nnimap "imap.gmail.com"
(nnimap-address "imap.gmail.com")
(nnimap-server-port 993)
(nnimap-stream ssl)))

(setq smtpmail-starttls-credentials '(("smtp.gmail.com" 587 nil nil))
smtpmail-smtp-server "smtp.gmail.com"
smtpmail-default-smtp-server "smtp.gmail.com"
send-mail-function 'smtpmail-send-it
message-send-mail-function 'smtpmail-send-it
smtpmail-smtp-service 587
smtpmail-auth-credentials '(("smtp.gmail.com"
587
"huzhili@gmail.com"
nil)))
(add-hook 'gnus-topic-mode-hook 'gnus-topic-mode)