code: def ft_search keyword:, offset: 0, num: 10, filter: {}
        if filter[:numeric_field].blank?
          results = REDI_SEARCH.call('FT.SEARCH', @index_name, keyword.strip,
            'LIMIT', offset, num)
        else
          results = REDI_SEARCH.call('FT.SEARCH', @index_name, keyword.strip,
            'LIMIT', offset, num,
            'FILTER', filter[:numeric_field], filter[:min], filter[:max]
          )
        end
        #'NOCONTENT', 'VERBATIM',  'WITHSCORES', 'NOSTOPWORDS', 'WITHPAYLOADS',
        #'INKEYS', 'INFIELDS', 'SLOP', 'LANGUAGE', 'EXPANDER', 'SCORER', 'PAYLOAD', 'SORTBY'
        return results
      rescue Exception => e
        Rails.logger.error e if defined? Rails
        return e.message
      end
docs: search the index for specific keyword(s)
  
   @param keyword [String]  'some keyword'
   @param offset [Integer]   default 0
   @param keyword [Integer]  default 10
   @return [Array]   [1, "gid://application_name/User/unique_id", ["name", "Bob", "age", "100"]]
   @raise [RuntimeError]