add nixos module (#22)

main/flake.nix

@@ -1,6 +1,7 @@
 {
   inputs = {
     nixpkgs-stable.url = "github:nixos/nixpkgs/nixos-23.11";
+    nixpkgs-22-11.url = "github:nixos/nixpkgs/nixos-22.11";
     nixpkgs-23-05.url = "github:nixos/nixpkgs/nixos-23.05";
     nixpkgs-stable-2023-07-25.url = "github:nixos/nixpkgs/6dc93f0daec55ee2f441da385aaf143863e3d671";
     nixpkgs-master-2023-05-06.url = "github:nixos/nixpkgs/16b3b0c53b1ee8936739f8c588544e7fcec3fc60";
@@ -10,11 +11,13 @@
     flake-utils.url = "github:numtide/flake-utils";
   };
   outputs = inputs:
-    inputs.flake-utils.lib.eachDefaultSystem (system:
+    (inputs.flake-utils.lib.eachDefaultSystem (system:
       rec {
         packages = import ./packages.nix { inherit inputs system; };
         lib = import ./lib.nix { inherit inputs system packages; };
         checks = import ./checks.nix { inherit inputs system packages lib; };
-      }
-    );
+      })
+    ) // {
+      nixosModules = import ./nixos-modules.nix { inherit inputs; };
+    };
 }

main/nixos-modules.nix

@@ -0,0 +1,31 @@
+{ inputs }:
+{
+  docker-for-local-dev =
+    { config, ... }:
+    let
+      pkgs = import inputs.nixpkgs-22-11 { inherit (config.nixpkgs) system; };
+    in
+    {
+      # Enable Docker
+      virtualisation.docker.enable = true;
+
+      # Allow Docker to see the host
+      networking.firewall.allowedTCPPorts = [ 3000 ];
+
+      # Pretend that localhost.com is a domain that points to our own machine
+      networking.extraHosts = ''
+        127.0.0.1 localhost.com
+        127.0.0.1 api.localhost.com
+        127.0.0.1 assets.localhost.com
+        127.0.0.1 classroom.localhost.com
+        127.0.0.1 school.localhost.com
+        127.0.0.1 student.localhost.com
+        127.0.0.1 console.localhost.com
+        127.0.0.1 faktory.localhost.com
+        127.0.0.1 tts.localhost.com
+        127.0.0.1 sso.localhost.com
+      '';
+
+      virtualisation.docker.package = pkgs.docker;
+    };
+}