[Miso] Adds Miso cache to Vega

system/hosts/vega/cachix.nix

@@ -0,0 +1,13 @@
+# WARN: `cachix use` will write to /etc/nixos/.  You will need to update this file manually.
+{ lib, ... }:
+
+let
+  folder = ./cachix;
+  toImport = name: value: folder + ("/" + name);
+  filterCaches = key: value: value == "regular" && lib.hasSuffix ".nix" key;
+  imports = lib.mapAttrsToList toImport (lib.filterAttrs filterCaches (builtins.readDir folder));
+in
+{
+  inherit imports;
+  nix.settings.substituters = [ "https://cache.nixos.org/" ];
+}