Set up automatic garbage collection

README.md

@@ -4,7 +4,6 @@
 
 - Make rofi power menu work by removing password requirement from shutdown, reboot, etc., which is normally done with `visudo` (see [this Stack Overflow thread](https://askubuntu.com/a/168885) and [Nix `sudo` option](https://search.nixos.org/options?channel=22.05&from=0&size=50&sort=relevance&type=packages&query=sudo).
 - Package safe poweroff bash script required by rofi power menu
-- Limit number of stored rollbacks to remove need for manual garbage collection
 - Theme lightdm
 - Theme GRUB
 - Find out how handling multiple hosts works so both desktop and ThinkPad configurations are buildable from flake

configuration.nix

@@ -14,6 +14,12 @@ in
       #<home-manager/nixos>
     ];
 
+  # Automatically delete generations older than a week
+  nix.gc = {
+    automatic = true;
+    options = "--delete-generations 8d";
+  };
+
   # Use the GRUB 2 boot loader.
   boot.loader = {
     efi = {