v0.2.0

• v0.2.0

1. Supports Redis
2. Add a simple database implementation PickleDbClient
3. Supports ForeignKeyField
4. Add Model.replace() and Model.get_or_create() method
5. Add Field.startswith() query
6. [MongoDB/Redis] Auto create index when field with attr index=True or unique=True
7. Fix DoesNotExist not found error