anchor.diff:        database_args = mkOption {
           type = types.attrs;
           default = {
  -          database = "/var/lib/matrix-synapse/homeserver.db";
  +          database = "${cfg.dataDir}/homeserver.db";
           };
           description = ''
             Arguments to pass to the engine.
  
positive.code: federation_rc_sleep_delay: ${cfg.federation_rc_sleep_delay}
  federation_rc_reject_limit: ${cfg.federation_rc_reject_limit}
  federation_rc_concurrent: ${cfg.federation_rc_concurrent}
  media_store_path: "/var/lib/matrix-synapse/media"
  uploads_path: "/var/lib/matrix-synapse/uploads"
  max_upload_size: "${cfg.max_upload_size}"
  max_image_pixels: "${cfg.max_image_pixels}"
  dynamic_thumbnails: ${boolToString cfg.dynamic_thumbnails}
  
negative.code:     users.extraUsers = [
        { name = "matrix-synapse";
          group = "matrix-synapse";
          home = cfg.dataDir;
          createHome = true;
          shell = "${pkgs.bash}/bin/bash";
          uid = config.ids.uids.matrix-synapse;
  