def download_groups(id)
      doc = permissions_doc(id)
      return [] if doc.nil?
      groups = Array(doc[self.class.read_group_field]) + Array(doc[self.class.edit_group_field])
      Rails.logger.debug("[CANCAN] download_groups: #{groups.inspect}")
      groups
    end
def download_groups(id)
      doc = permissions_doc(id)
      return [] if doc.nil?
      groups = Array(doc[self.class.read_group_field]) + Array(doc[self.class.edit_group_field])
      Rails.logger.debug("[CANCAN] download_groups: #{groups.inspect}")
      groups
    end
Samvera doesn't use download user/groups, so make it an alias to read
 Grant all groups with read or edit access permission to download