Enable weekly automatic garbage collection

configuration.nix

@@ -15,12 +15,22 @@
   boot.loader.grub.device = "/dev/vda";
   boot.loader.grub.useOSProber = true;
 
-  # Enable autoupgrade
+  # Autoupgrade
   system.autoUpgrade = {
     enable = true;
     channel = "https://nixos.org/channels/nixos-unstable";
   };
 
+  # Garbage collection
+  nix = {
+    settings.auto-optimise-store = true;
+    gc = {
+      automatic = true;
+      dates = "weekly";
+      options = "--delete-older-than 7d";
+    };
+  };
+
   networking.hostName = "nixos"; # Define your hostname.
   # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.