mysql: enable backups

modules/mysql.nix

@@ -5,4 +5,16 @@
     package = pkgs.mariadb;
     settings.mysqld.bind_address = "127.0.0.1";
   };
+  services.mysqlBackup = {
+    enable = true;
+    user = "mysql";
+    location = "/var/lib/backup/mysql";
+    databases = [
+      "decisions"
+      "fsrewsp"
+      "nightline"
+      "wiki_ese"
+      "wiki_vernetzung"
+    ];
+  };
 }