feat: add back my rust template

templates/rust/flake.nix

@@ -0,0 +1,69 @@
+{
+  inputs = {
+    crane.url = "github:ipetkov/crane";
+    crane.inputs.nixpkgs.follows = "nixpkgs";
+    fenix.url = "github:nix-community/fenix";
+    fenix.inputs.nixpkgs.follows = "nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+  };
+
+  outputs = {
+    crane,
+    flake-utils,
+    nixpkgs,
+    ...
+  } @ inputs:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        inherit (pkgs) lib;
+        pkgs = import nixpkgs {inherit system;};
+        fenix = inputs.fenix.packages.${system};
+        craneLib = crane.lib.${system}.overrideToolchain toolchain.toolchain;
+        mkSrc = extraPaths:
+          with lib.fileset; let
+            root = ./.;
+            rustFiles = fromSource (craneLib.cleanCargoSource root);
+            fileset = union rustFiles (unions extraPaths);
+          in
+            toSource {inherit root fileset;};
+
+        ## Customize here ##
+        toolchain = fenix.complete; # or fenix.stable;
+        stdenv = pkgs.stdenvAdapters.useMoldLinker pkgs.stdenv;
+      in {
+        packages.default = craneLib.buildPackage {
+          inherit stdenv;
+          src = mkSrc [];
+          strictDeps = true;
+          buildInputs =
+            [
+              # Add additional build inputs here
+            ]
+            ++ lib.optionals pkgs.stdenv.isDarwin [
+              # Additional darwin specific inputs can be set here
+              pkgs.libiconv
+            ];
+          # Additional environment variables can be set directly
+          # MY_CUSTOM_VAR = "some value";
+        };
+
+        devShells.default =
+          pkgs.mkShell.override {inherit stdenv;}
+          {
+            nativeBuildInputs = with pkgs;
+              [
+                # Add additional build inputs here
+              ]
+              ++ (with toolchain; [
+                cargo
+                clippy
+                rustfmt
+                rustc
+                fenix.rust-analyzer
+              ]);
+            RUST_SRC_PATH = "${toolchain.rust-src}/lib/rustlib/src/rust/library";
+          };
+      }
+    );
+}