modules: move 'services' into subfolder

modules/services/postgresql-backup.nix

@@ -0,0 +1,28 @@
+# Backup your data, kids!
+{ config, lib, ... }:
+let
+  cfg = config.my.services.postgresql-backup;
+in
+{
+  options.my.services.postgresql-backup = {
+    enable = lib.mkEnableOption "Backup SQL databases";
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.postgresqlBackup = {
+      enable = true;
+      backupAll = true;
+      location = "/var/backup/postgresql";
+    };
+
+    my.services.backup = {
+      paths = [
+        config.services.postgresqlBackup.location
+      ];
+      # No need to store previous backups thanks to `restic`
+      exclude = [
+        (config.services.postgresqlBackup.location + "/*.prev.sql.gz")
+      ];
+    };
+  };
+}