Every new Play app gets a new application secret generated into its config file.
application.secret=asdfadsfdasf
I\'m developing an open source app
You can externalize the secret as an environment variable.
In conf/application.conf
Simply replace
application.secret=abc123...
with
application.secret=${APP_SECRET}
and then set this config var in Heroku with:
$ heroku config:add APP_SECRET=abc123...
Now you can manage secrets on a per-app basis and avoid checking them into version control.