add: added atuin overlay

flake.nix

@@ -7,9 +7,22 @@
     home-manager.url = "github:nix-community/home-manager";
     darwin.url = "github:LnL7/nix-darwin";
     darwin.inputs.nixpkgs.follows = "nixpkgs";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
-  outputs = inputs@{ self, nixpkgs, flake-utils, home-manager, darwin, ... }:
+  outputs =
+    inputs@{
+      self,
+      nixpkgs,
+      flake-utils,
+      home-manager,
+      darwin,
+      rust-overlay,
+      ...
+    }:
     let
       systems = [
         "x86_64-linux"
@@ -19,7 +32,8 @@
       forAllSystems = f: nixpkgs.lib.genAttrs systems f;
     in
     {
-      packages = forAllSystems (system:
+      packages = forAllSystems (
+        system:
         let
           pkgs = import nixpkgs {
             inherit system;
@@ -29,18 +43,24 @@
         import ./pkgs { inherit pkgs; }
       );
 
-      devShells = forAllSystems (system:
-        let pkgs = import nixpkgs { inherit system; }; in
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+        in
         {
           default = pkgs.mkShell {
-            packages = with pkgs; [ 
-              nixfmt-rfc-style 
+            packages = with pkgs; [
+              nixfmt-rfc-style
             ];
           };
         }
       );
 
-      overlays.default = import ./overlays;
+      overlays.default = nixpkgs.lib.composeManyExtensions [
+        rust-overlay.overlays.default
+        (import ./overlays)
+      ];
       homeManagerModules = import ./modules/home-manager self;
       nixosModules.default = import ./modules/nixos;
       darwinModules.default = import ./modules/darwin;