On Heroku, I am trying to copy the production database into my staging app using the pgbackups addon. I followed the instructions on the addon page: https://devcenter.heroku.com
UPDATE:
You can run this command to transfer the database from production to staging:
heroku pg:copy your-app::DATABASE_URL DATABASE_URL -a yourapp-staging
It will prompt you to confirm the action, and once you have done that, all of the data will be migrated.