+ ${if cfg.logo != null
          then ''HYDRA_LOGO="${cfg.logo}" ''
          else ""}

        example = "dbi:SQLite:/home/hydra/db/hydra.sqlite";

          The DBI string for Hydra database connection

          The DBI string for Hydra database connection.

      }; 
      

      };
      logo = mkOption {
        default = null;
        description = ''
          File name of an alternate logo to be displayed on the web pages.
        '';
      };