My flake.nix for System Configuration

flake.nix

  description = "JSJ's System Config";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-21.05";
    home-manager.url = "github:nix-community/home-manager/release-21.05";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { self, nixpkgs, home-manager, ... }: 
  let
    system = "x86_64-linux";

    pkgs = import nixpkgs {
      inherit system;
      config = { allowUnfree = true; };
    };

    lib = nixpkgs.lib;

  in {
    nixosConfigurations = {
      nixos = lib.nixosSystem {
        inherit system;

        modules = [
          ./system/configuration.nix
        ];
      };
    };
  };
}