WIP: add notes for missing persistence/backup

TODO:
* Do home-manager
* Look at for more inspiration github.com:nix-community/impermanence/pull/108
* Common files github.com:nix-community/impermanence/issues/10
* Useful config: github.com:chayleaf/dotfiles/blob/f77271b249e0c08368573c22a5c34f0737d3a766/system/modules/impermanence.nix

modules/nixos/services/drone/runner-docker/default.nix

@@ -39,5 +39,7 @@ in
       extraGroups = [ "docker" ]; # Give access to the daemon
     };
     users.groups.drone-runner-docker = { };
+
+    # FIXME: persistence?
   };
 }

modules/nixos/services/drone/runner-exec/default.nix

@@ -63,5 +63,7 @@ in
       group = "drone-runner-exec";
     };
     users.groups.drone-runner-exec = { };
+
+    # FIXME: persistence?
   };
 }

modules/nixos/services/drone/server/default.nix

@@ -50,5 +50,7 @@ in
         inherit (cfg) port;
       };
     };
+
+    # FIXME: persistence?
   };
 }