{ pkgs ? import <nixpkgs> {} }: 

let app = (pkgs.callPackage ../backend/default.nix {}).package ; 
in 
pkgs.dockerTools.buildImage {
  name = "gotta-catch-them-all-backend";
  tag = "latest";
  contents = [ pkgs.nodejs app ];
  config = {
    ExposedPorts = {
      "5000/tcp" = {};
    };
    Cmd = [ "${pkgs.nodejs}/bin/node" "${app}/bin/gotta-catch-them-all" ];
  };
}