rabl 0.11.6 causes custom root object label to say "string"

[aripollak]

Under Rails 4.1.8, if I have a simple view defined like this:

object @foo => 'foo'
attributes :data, :id

and the controller sets @foo to be a FooPresenter, then upgrading from rabl 0.11.5 to 0.11.6 changes the rendered JSON output from this:
"foo" => {"data"=>"bar", "id"=>3250}
to this:
"string" => {"data"=>"bar", "id"=>3250}

I've tracked it down to this change. I'm not really sure what's going on there, but it looks like it's causing class name of the last part of the object hash to be stringified? Changing the 'foo' to :foo in the view does not exhibit the problem.

[nesquena]

@DouweM Could you take a look?

[johnnaegle]

Also seeing this