docs: update readme

README.md

@@ -1,14 +1,63 @@
 # nix-base
 
-My public nix base configuration (Mac+Linux) i use in my personal and work configurations.
+[![Build Status](https://github.com/ojsef39/nix-base/actions/workflows/validate.yml/badge.svg)](https://github.com/ojsef39/nix-base/actions/workflows/validate.yml)
+![GitHub repo size](https://img.shields.io/github/repo-size/ojsef39/nix-base)
+![GitHub License](https://img.shields.io/github/license/ojsef39/nix-base)
 
-## Usage & Folder Structure
+This repository contains my public Nix base configuration for both macOS and Linux systems.
 
-See example: <https://github.com/ojsef39/nix-personal>
+It is designed to be used as an input in another nix config, see an example: [ojsef39/nix-personal](https://github.com/ojsef39/nix-personal)
+
+## Structure
+
+```
+
+```
 
 ## TODOs
 
 - [ ] Move pkgs for all systems to shared/pkgs.nix
   - [ ] Move packages to where they get used e.g. eza to shell/default.nix
 - [ ] Use Vesktop instead of Discord
 - [ ] Update READMEs
+
+## Key Files and Their Purpose
+
+### Top-Level Files
+
+- `flake.nix`: Entry point for the Nix flake configuration, defining inputs and outputs.
+- `Makefile`: Automation scripts for building and deploying configurations.
+- `renovate.json`: Configuration for dependency updates.
+
+### Shared Configuration
+
+- `nix/core.nix`: Core Nix configurations shared across all systems.
+
+- `hosts/shared/`: Shared configurations and programs used by both macOS and Linux.
+  - `import.nix`: Imports shared program modules.
+  - `programs/`: Contains configurations for various programs:
+    - `editor/`
+    - `git/`
+    - `kitty/`
+    - `shell/`
+    - `ssh/`
+    - `yuki/`
+    - `…`
+
+### macOS Configuration (`nix-darwin`)
+
+- `hosts/darwin/`:
+  - `import.nix`: Imports macOS-specific modules.
+  - `system.nix`: System-level settings and preferences for macOS.
+  - `homebrew.nix`: Homebrew package configurations (gets imported seperately).
+  - `apps.nix`: Additional applications to install on macOS.
+
+## Useful commands for upstream nix configuration
+
+Check if Brew list got merged correctly:
+
+`nix eval .#darwinConfigurations.mac.config.homebrew.masApps`
+
+Check if programs got merged correctly:
+
+`nix eval .#darwinConfigurations.mac.config.system.programs.zsh.sessionVariables.PATH`