def revisionable_associations(options = acts_as_revisionable_options[:associations])
      return nil unless options
      options = [options] unless options.kind_of?(Array)
      associations = {}
      options.each do |association|
        if association.kind_of?(Symbol)
          associations[association] = true
        elsif association.kind_of?(Hash)
          association.each_pair do |key, value|
            associations[key] = revisionable_associations(value)
          end
        end
      end
      return associations
    end
def revisionable_associations(options = acts_as_revisionable_options[:associations])
      return nil unless options
      options = [options] unless options.kind_of?(Array)
      associations = {}
      options.each do |association|
        if association.kind_of?(Symbol)
          associations[association] = true
        elsif association.kind_of?(Hash)
          association.each_pair do |key, value|
            associations[key] = revisionable_associations(value)
          end
        end
      end
      return associations
    end
Returns a hash structure used to identify the revisioned associations.