This is the heroku washtub command line plugin.
Go see the clean data obsessed kids over at washtubapp.com and sign up.
Then install the plugin
heroku plugins:install heroku-washtub
Then you can initialize the washtub
heroku washtub:init --app yourappname
Then visit the app and set your data anonymization policy.
Next you submit a wash.
heroku pg:backups:capture
heorku washtub:wash backupid local_development_database
Now you've got a clean data set to work with!
NOTE: This will overwrite the database called local_development_database.