Add shellinabox

Add shellinabox.

Currently I run this with the following service. Should I add this into nixos/modules/services/web-servers/shellinabox.nix  Add some options for the configuration? If yes, what are some good examples to crib off of?

 systemd.services = {
      shellinaboxd = {
        description = "shellinabox web server.";
        path = [ pkgs.shellinabox pkgs.openssh];
        script = ''shellinaboxd --css ${pkgs.shellinabox}/share/doc/shellinabox/white-on-black.css --no-beep --disable-ssl  --localhost-only -s /:SSH'';
        wantedBy = [ "multi-user.target" ];
        requires = [ "network.target" ];
      };
    };