add my own game to exported pkgs

pkgs/default.nix

@@ -1,15 +1,12 @@
-{ default, ... }: 
-{
-  systems = ["x86_64-linux"];
-
-  perSystem = {
-    pkgs,
-    inputs',
-    ...
-  }: {
-    packages = {
-      _2048 = pkgs.callPackage ./2048 {};
-      
-    };
-  };
-}
+rec{
+  overlay = final: prev:
+    let
+      dirContents = builtins.readDir ../pkgs;
+      genPackage = name: {
+        inherit name;
+        value = final.callPackage (../pkgs + "/${name}") { };
+      };
+      names = builtins.attrNames dirContents;
+    in
+    builtins.listToAttrs (map genPackage names);
+}