http://www.pythondoc.com/flask-login/
http://www.bjhee.com/flask-ext8.html
https://www.jianshu.com/p/06bd93e21945
https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-v-user-logins
http://www.pythondoc.com/flask-login/
http://www.bjhee.com/flask-ext8.html
https://www.jianshu.com/p/06bd93e21945
https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-v-user-logins