added Procfile for heroku

Sorry I neglected to add a Procfile with my previous commit :(

This is what I did to test:

    git pull
    git checkout -b tom_heroku_deploy
    $EDIT Procfile
    git add Procfile
    git status
    git commit -a -m 'added Procfile for heroku'
    heroku apps:create chat-tmarble1
    git push heroku tom_heroku_deploy:master
    heroku open
    git push --set-upstream origin tom_heroku_deploy

Does that match the required functionality?