Deploying new user authentication (working) to Heroku

 - updates User and Talk models
 - updates controller
 - checks if talk is empty or a dupe
 - checks if User exists or not (doesn't create dupes anymore)
Deploying to heroku, fixed past talks
Cleanup - moves methods out of controller, new flash messages

 - flash message based on if you are a new user or already a user
 - moves production_database_config method to Database class
   (for cleaning up controller)
 - saves username into session, for some reason wasn't working to pull
   into '/' route