grouping_queries

# File activerecord/lib/active_record/relation/predicate_builder.rb, line 140
      def grouping_queries(queries)
        if queries.one?
          queries.first
        else
          queries.map! { |query| query.reduce(&:and) }
          queries = queries.reduce { |result, query| Arel::Nodes::Or.new(result, query) }
          Arel::Nodes::Grouping.new(queries)
        end
      end