nix: init flake

nix/flake.nix

@@ -0,0 +1,19 @@
+{
+  description = "nico's linux system.";
+
+  inputs = {
+    # NixOS official package source, using the unstable branch here
+    nixpkgs.url = "github:NixOS/nixpkgs/unstable";
+  };
+
+  outputs = { self, nixpkgs, ... }@inputs: {
+    nixosConfigurations.pluto = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules = [
+        ./configuration.nix
+        ./hosts/pluto/conf.nix
+        ./hosts/pluto/hardware-configuration.nix
+      ];
+    };
+  };
+}