def fields
      tripod_superclasses.map { |c| c.instance_variable_get(:@fields) }.reduce do |acc,class_fields|
        class_fields.merge(acc)
      end
    end
def fields
      tripod_superclasses.map { |c| c.instance_variable_get(:@fields) }.reduce do |acc,class_fields|
        class_fields.merge(acc)
      end
    end
Return all of the fields on a +Resource+ in a manner that
 respects Ruby's inheritance rules.  i.e. subclass fields should
 override superclass fields with the same