This adds support for nested_form when using formtastic or simple_form.
Add NestedForm::SimpleBuilder and NestedForm::FormtasticBuilder
I'll try to add some.
Add tests for NestedForm::FormtasticBuilder and NestedForm::SimpleBui…
I've added tests now. Since the new builders internally just is different names for the normal simple form and formtastic builders I just copied the other tests and changed the name.
Pulled in, sorry it took so long!