rails/rails — pull request #12000 by wangjohn (2013-08-23 16:35:27+00:00)
Title: Deprecating passing strings as class name in fixtures.

Inside of fixtures, you can do the following:

```ruby
set_fixture_class some_fixture: SomeModel,
another_fixture: "AnotherModel"
```

The ability to pass in the model name as a string is redundant and should probably be deprecated.