title: AWS lambda serverless website session maintaining
body: <p>I developed a website using node.js as back-end.
  Recently I am trying to make it serverless and deploy to lambda.
  I will re-write most of my code but just haven't figured out how to maintain the session after user logged in. I was using "express-session" module and the session data is all recorded in the database.</p>
  
  <p>To be honest I don't have a very deep understanding on sessions. 
  I searched on google and did not find what I need. 
  Does anyone have some sample code on maintaining sessions using lambda?
  or any resources. Thanks a lot!</p>