docs: add nixos installation

site/docs/getting_started/installation.md

@@ -1,3 +1,8 @@
+# Welcome to Dooit!
+
+Thank you for installing dooit! I hope you enjoy it. \
+Feel free to open any feature requests if you have great ideas
+
 Dooit can be installed via various package managers
 
 ## PyPI
@@ -14,6 +19,62 @@ yay -S dooit-bin dooit-extras
 
 ## NixOS
 
+### Flakes :snowflake:
+
+```nix{25,7-8,}
+# flake.nix
+
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; # this can be stable, but if it is do not make hyprpanel follow it
+
+    dooit.url = "github:kraanzu/dooit/develop";
+    dooit-extras.url = "github:dooit-org/dooit-extras";
+  };
+  # ...
+
+  outputs = inputs @ {
+    nixpkgs,
+    ...
+  }: let
+    pkgs = import nixpkgs {};
+    system = "x86_64-linux"; # change to whatever your system should be
+  in {
+    nixosConfigurations."${host}" = nixpkgs.lib.nixosSystem {
+      specialArgs = {
+        inherit system inputs pkgs;
+      };
+      modules = [
+        # ...
+        ./dooit.nix
+      ];
+    };
+  };
+}
+```
+
 ```nix
+# dooit.nix
+
+{
+  inputs,
+  pkgs,
+  ...
+}: let
+  mydooit = pkgs.dooit.override {
+    extraPackages = [
+      pkgs.dooit-extras
+    ];
+  };
+in {
 
+  # this overlay allows you to use dooit from pkgs.dooit
+  nixpkgs.overlays = [inputs.dooit.overlay inputs.dooit-extras.overlay];
+
+  environment.systemPackages = [
+    mydooit
+  ];
+}
 ```
+
+> Thanks to [`Hyprpanel`](https://hyprpanel.com/) from whom I stole the format for the flake