add poetry template

templates/poetry/flake.nix

@@ -0,0 +1,27 @@
+{
+  description = "Python project flake";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs";
+  inputs.poetry2nix.url = "github:nix-community/poetry2nix";
+
+  outputs = { self, nixpkgs, flake-utils, poetry2nix }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ poetry2nix.overlay ];
+        };
+        projectDir = ./.;
+
+      in {
+        defaultPackage =
+          pkgs.poetry2nix.mkPoetryApplication { inherit projectDir; };
+        devShells.default = pkgs.mkShell {
+          buildInputs = [
+            (pkgs.poetry2nix.mkPoetryEnv { inherit projectDir; })
+            pkgs.poetry
+          ];
+        };
+      });
+}