modules: nix: pin flake registry to common inputs

modules/nix.nix

@@ -1,9 +1,17 @@
 # Nix related settings
-{ pkgs, ... }:
+{ inputs, pkgs, ... }:
 
 {
   nix = {
     package = pkgs.nixFlakes;
+    registry = {
+      # Allow me to use my custom package using `nix run self#pkg`
+      self.flake = inputs.self;
+      # Do not follow master, use pinned revision instead
+      nixpkgs.flake = inputs.nixpkgs;
+      # Add NUR to run some packages that are only present there
+      nur.flake = inputs.nur;
+    };
     extraOptions = ''
       experimental-features = nix-command flakes
     '';