or

# File activerecord/lib/active_record/relation/where_clause.rb, line 40
      def or(other)
        left = self - other
        common = self - left
        right = other - common

        if left.empty? || right.empty?
          common
        else
          left = left.ast
          left = left.expr if left.is_a?(Arel::Nodes::Grouping)

          right = right.ast
          right = right.expr if right.is_a?(Arel::Nodes::Grouping)

          or_clause = Arel::Nodes::Or.new(left, right)

          common.predicates << Arel::Nodes::Grouping.new(or_clause)
          common
        end
      end