feat(backup): first borgbackup module test

https://xeiaso.net/blog/borg-backup-2021-01-09/

nixos/borgbackup.nix

@@ -0,0 +1,37 @@
+{
+  services.borgbackup.jobs."borgbase" = {
+    paths = [
+      # server storage
+      "/var/lib/postgresql"
+      "/var/lib/sourcehut"
+      # user storage
+      "/home"
+    ];
+    exclude = [
+      # remote mounted folders
+      "/home/khais/Music"
+      "/home/khais/Books"
+      # scratch directories
+      "/home/*/Downloads"
+      "/home/*/.local"
+      # cache & trash directories
+      "**/*cache"
+      "**/*Cache"
+      "**/*trash"
+      "**/*Trash"
+      # already cloud apps
+      "**/.mozilla/firefox"
+      # build-output directories
+      "**/target"
+      "**/result"
+    ];
+    repo = "lni0x30f@lni0x30f.repo.borgbase.com:repo";
+    encryption = {
+      mode = "repokey-blake2";
+      passCommand = "cat /root/borgbackup/passphrase";
+    };
+    environment.BORG_RSH = "ssh -i /root/borgbackup/ssh_key";
+    compression = "auto,lzma";
+    startAt = "daily";
+  };
+}

nixos/configuration.nix

@@ -8,6 +8,7 @@
     [ # Include the results of the hardware scan.
       ./hardware-configuration.nix
       ./sourcehut.nix
+      ./borgbackup.nix
     ];
 
   # Bootloader.