};
  # some development thing I made on the spot.
  services.postgresql = {
    enable = true;
    package = pkgs.postgresql_10;
    enableTCPIP = true;
    authentication = pkgs.lib.mkOverride 10 ''
      local all all trust
      host all all ::1/128 trust
      host all all 127.0.0.1/32 trust
    '';