Solve Hashie::Mash indifferent access StackError

See #164.
Use this:

"This set of tests verifies that Hashie::Extensions::IndifferentAccess works with ActiveSupport HashWithIndifferentAccess hashes. See https://github.com/intridea/hashie/issues/164 and https://github.com/intridea/hashie/issues/166 for details."