Add rake test description

No behavior change
Fix ActiveRecord `subclass_from_attrs` when eager_load is false.
It cannot find subclass because all classes are loaded automatically
when it needs.
Merge pull request #9497 from route/subclass_from_attrs

Fix ActiveRecord `subclass_from_attrs` when eager_load is false.

Conflicts:
	activerecord/CHANGELOG.md
Avoid short-circuit return
Make sure options is a hash
The console --sandbox transaction should not be joinable

Thanks @neerajdotname for noticing this bug.
Fix changelog indent, remove self from method call in changelog/doc examples

[ci skip]
Refactored nested associations so they are more readable. Added comments
which make it clearer about what's going on.
Merge pull request #9614 from wangjohn/refactoring_nested_associations_for_readability

Refactored nested associations so they are more readable.
Merge pull request #8670 from sanemat/fix/rake-desc

Add rake test description