Follow these 4 simple steps in your terminal (Heroku Dev Center): Create a backup copy of your database:
$ heroku pg:backups capture DATABASE_NAME
Download the copy from Heroku (to your local machine) using curl:
$ curl -o latest.dump `heroku pg:backups public-url`
Load it*:
$ pg_restore --verbose --clean --no-acl --no-owner -h localhost -U YOUR_USERNAME -d DATABASE_NAME latest.dump
get YOUR_USERNAME
and choose the desired database from your config/database.yml file.
DATABASE_NAME
can be your development/test/production db (Ex. mydb_development)
That's it!