River is a open source workflow system for Django which support on the fly changes on every item in workflow instead of hardcoding states and transitions. Main goal of developing this framework is to be able to edit any workflow item on the fly. This means, all elements in workflow like states, transitions, user authorizations(permission), group authorization are editable. To do this, all data about the workflow item is persisted into DB. Hence, they can be changed without touching the code and re-deploying your application.