Add an example nixos config using this site

nixos-configuration/flake.nix

@@ -0,0 +1,49 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    our-site = {
+      url = "git+ssh://gitea@gitea.kalu.blue/tech-blog/create-a-static-blog-with-nix.git?ref=main&shallow=1";
+      inputs.nixpkgs.follows = "nixpkgs"; # Will use the same Nixpkgs as the NixOS system
+    };
+  };
+
+  outputs =
+    { self, nixpkgs, ... }@inputs:
+    {
+      nixosConfigurations.my-server-name = nixpkgs.lib.nixosSystem {
+        specialArgs = {
+          # These will be passed as arguments to the modules
+          inherit inputs;
+        };
+
+        modules = [
+          # Essential for test VM
+          {
+            virtualisation.vmVariant = {
+              virtualisation = {
+                memorySize = 2048;
+                cores = 2;
+                # Disable graphics to avoid gtk error
+                graphics = false;
+              };
+            };
+
+            # Create a user, so we can login and test
+            users.users.test = {
+              isNormalUser = true;
+              # Never use this, use `hashedPassword` instead
+              initialPassword = nixpkgs.lib.mkForce "123123";
+              # So we can use `sudo` mainly for `sudo shutdown now` and to be able to debug `caddy`
+              group = "wheel";
+            };
+          }
+          # Some configuration
+          {
+            nixpkgs.hostPlatform = "x86_64-linux";
+            system.stateVersion = "25.11";
+          }
+          ./my-static-site.nix
+        ];
+      };
+    };
+}