adding overlay for portunus

modules/ldap.nix

@@ -123,4 +123,18 @@ in
       };
     };
   };
+
+  nixpkgs.overlays = [
+    (self: super:
+{
+  portunus = super.portunus.overrideAttrs (old: {
+    src = super.fetchFromGitHub {
+      owner = "revol-xut";
+      repo = "portunus";
+      rev = "4dc29febacb11c613785bc95352fa00e0ca9b14a";
+      sha256 = "sha256-6O2392aHXhgvgZf6ftDY5Bh6hG3OzzCnlriig/Vkkz8=";
+    };
+  });
+})
+];
 }