instance method add_enum_value

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 603
      def add_enum_value(type_name, value, **options)
        before, after = options.values_at(:before, :after)
        sql = +"ALTER TYPE #{quote_table_name(type_name)} ADD VALUE"
        sql << " IF NOT EXISTS" if options[:if_not_exists]
        sql << " #{quote(value)}"

        if before && after
          raise ArgumentError, "Cannot have both :before and :after at the same time"
        elsif before
          sql << " BEFORE #{quote(before)}"
        elsif after
          sql << " AFTER #{quote(after)}"
        end

        execute(sql).tap { reload_type_map }
      end