Add custom impermanence module

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/system/configs/docker/default.nix

@@ -1,4 +1,4 @@
-{ pkgs, ... }:
+{ config, pkgs, ... }:
 {
   virtualisation.docker = {
     enable = true;
@@ -18,7 +18,12 @@
   };
 
   environment = {
-    persistence."/persist".directories = [ "/var/lib/docker" ];
+    persistence."/persist"."/var/lib/docker" = { };
     systemPackages = with pkgs; [ docker-compose ];
   };
+
+  systemd = {
+    services.docker.after = [ config.environment.persistence."/persist"."/var/lib/docker".mount ];
+    sockets.docker.after = [ config.environment.persistence."/persist"."/var/lib/docker".mount ];
+  };
 }