so basically :
Multi Session Tech :
https://github.com/codenoid/phoenix-auth-example/blob/master/multi/lib/multi_web/controllers/page_controller.ex https://github.com/codenoid/phoenix-auth-example/blob/master/multi/lib/multi_web/helper/session.ex
Single Session Tech :
https://github.com/codenoid/phoenix-auth-example/blob/master/single/lib/single/application.ex https://github.com/codenoid/phoenix-auth-example/blob/master/single/lib/single_web/controllers/page_controller.ex https://github.com/codenoid/phoenix-auth-example/blob/master/single/lib/single_web/helper/session.ex
git clone https://github.com/codenoid/phoenix-auth-example
cd phoenix-auth-example
cd single # pick one
mix deps.get
cd assets && npm install
cd .. && mix phx.server
google-chrome "http://localhost:4000" # login 1
google-chrome "http://localhost:4000" --incognito # login 2, login 1 will be destroyed