Add a trimmed down version of my flake.nix

This is useful for showing others how my flake is structured.

examples/flake-structure.nix

@@ -0,0 +1,49 @@
+{
+  inputs = {};
+  outputs = inputs@{}: let
+    darwinHostConfig = { system, hostname, username, additionalModules, additionalSpecialArgs }:
+      nix-darwin.lib.darwinSystem { };
+
+    nixosHostConfig = { system, hostname, username, additionalModules, additionalSpecialArgs }:
+      nixpkgs.lib.nixosSystem { };
+    
+    linuxHomeConfig = { system, hostname, username, additionalModules, additionalSpecialArgs }:
+      home-manager.lib.homeManagerConfiguration { };
+
+  in {
+    # Darwin (macOS) hosts
+    darwinConfigurations = {
+      mightymac = darwinHostConfig {
+        system = "aarch64-darwin";
+        hostname = "mightymac";
+        username = "gene.liverman";
+        additionalModules = [];
+        additionalSpecialArgs = {};
+      };
+    };
+
+    # NixOS hosts
+    nixosConfigurations = {
+      rainbow-planet = nixosHostConfig {
+        system = "x86_64-linux";
+        hostname = "rainbow-planet";
+        username = "gene";
+        additionalModules = [
+          nixos-hardware.nixosModules.dell-xps-13-9360
+        ];
+        additionalSpecialArgs = {};
+      };
+    };
+
+    # Home Manager (only) users
+    homeConfigurations = {
+      gene = linuxHomeConfig {
+        system = "x86_64-linux";
+        hostname = "mini-watcher";
+        username = "gene";
+        additionalModules = [];
+        additionalSpecialArgs = {};
+      };
+    };
+  };
+}