How do I transfer production database to staging on Heroku using pgbackups? Getting error

Update for mid-2017 (stealing from Takehiro Mouri‘s answer – simplify the DATABSE_NAME part)

Update for mid-2015…

The pgbackups add-on has been deprecated. No more pgbackups:transfer.

To copy a database from yourapp to yourapp_staging:

# turn off the web dynos in staging
heroku maintenance:on -a yourapp-staging

# if you have non-web-dynos, do them too
heroku ps:scale worker=0 -a yourapp-staging

# backup the staging database if you are paranoid like me (optional)
heroku pg:backups capture -a yourapp-staging

# execute the copy
heroku pg:copy your-app::DATABASE_URL DATABASE_URL -a yourapp-staging

Then when it’s complete, turn staging back on:

# this is if you have workers, change '1' to whatever
heroku ps:scale worker=1 -a yourapp-staging

heroku maintenance:off -a yourapp-staging

(source: https://devcenter.heroku.com/articles/upgrading-heroku-postgres-databases#upgrade-with-pg-copy-default)