nix: add nix module and runnable VM

flake.nix

@@ -32,6 +32,20 @@
       };
     in f system pkgs toolchain);
   in {
+    apps = let
+      mkApp = program: description: {
+        type = "app";
+        program = toString program;
+        meta = {
+          inherit description;
+        };
+      };
+      mkVm = name: mkApp "${self.nixosConfigurations.${name}.config.system.build.vm}/bin/run-nixos-vm";
+    in forAllSystems (system: pkgs: _: {
+      default = self.apps.${system}.vm;
+      vm = mkVm "vm" "Start a NixOS VM with bro installed";
+    });
+
     devShells = forAllSystems (system: pkgs: toolchain: {
       default = pkgs.mkShell {
         nativeBuildInputs = with pkgs; [
@@ -53,6 +67,15 @@
       };
     };
 
+    nixosModules = {
+      default = self.nixosModules.bro;
+      bro = import ./nix/module.nix;
+    };
+
+    nixosConfigurations = {
+      vm = import ./nix/vm.nix { inherit self nixpkgs; };
+    };
+
     packages = forAllSystems (system: pkgs: _:
       let
       cargoToml = fromTOML (builtins.readFile ./Cargo.toml);