fix: increase of tmpfs's size by mount a btrfs subvolume for it

feat: migrate nixos-installer from a separate branch into a folder

hosts/idols/ai/nixos-installer/system.nix

@@ -0,0 +1,53 @@
+{pkgs, ...}: {
+  # Set your time zone.
+  time.timeZone = "Asia/Shanghai";
+
+  # Select internationalisation properties.
+  i18n.defaultLocale = "en_US.UTF-8";
+
+  i18n.extraLocaleSettings = {
+    LC_ADDRESS = "zh_CN.UTF-8";
+    LC_IDENTIFICATION = "zh_CN.UTF-8";
+    LC_MEASUREMENT = "zh_CN.UTF-8";
+    LC_MONETARY = "zh_CN.UTF-8";
+    LC_NAME = "zh_CN.UTF-8";
+    LC_NUMERIC = "zh_CN.UTF-8";
+    LC_PAPER = "zh_CN.UTF-8";
+    LC_TELEPHONE = "zh_CN.UTF-8";
+    LC_TIME = "zh_CN.UTF-8";
+  };
+
+  # ssh-agent is used to pull my private secrets repo from github when depoloying my nixos config.
+  programs.ssh.startAgent = true;
+
+  # List packages installed in system profile. To search, run:
+  # $ nix search wget
+  environment.systemPackages = with pkgs; [
+    neovim # Do not forget to add an editor to edit configuration.nix! The Nano editor is also installed by default.
+    git
+    gnumake
+    wget
+    curl
+    nix-output-monitor
+  ];
+
+  users.groups = {
+    "ryan" = {};
+  };
+
+  # Don't allow mutation of users outside the config.
+  users.mutableUsers = false;
+  # Define a user account. Don't forget to set a password with ‘passwd’.
+  users.users.ryan = {
+    # generated by `mkpasswd -m scrypt`
+    # we have to use initialHashedPassword here, if your'are using tmpfs for /
+    initialHashedPassword = "$7$CU..../....Sdl/JRH..9eIvZ6mE/52r.$xeR6lyvTcVVKt28Owcoc/vPOOECcYSiq1xjw/QCz2t0";
+    isNormalUser = true;
+    description = "ryan";
+    extraGroups = ["ryan" "networkmanager" "wheel"];
+  };
+  users.users.root.initialHashedPassword = "$7$CU..../....X6uvZYnFD.i1CqqFFNl4./$4vgqzIPyw5XBr0aCDFbY/UIRRJr7h5SMGoQ/ZvX3FP2";
+
+  # make ryan a trusted user so he can set custom nix substituters url(cache mirror) to speed up nixos-rebuild.
+  nix.settings.trusted-users = ["ryan"];
+}