2.0.0

• Unpin dj-database-url from a specific minor version to a specific major version.
• Initial support for deleting django models. I'm not going to update the docs just yet
  as I don't entirely like this solution...something is better than nothing.
  Check the test_deleted_model_in_settings tests to see this. The issue is that django
  needs to know about a model after you've deleted the class so sharded settings on deleted
  models need to be tracked somewhere.