add config to readme

Author: zekroTJA

README.md

@@ -4,7 +4,7 @@ A simple CLI tool to create screenshots from web pages in the terminal.
 
 This tool uses the [headless_chrome](https://crates.io/crates/headless_chrome) crate, which requires a local installation of Chrome or Chromium.
 
-> **Info**  
+> **Information**  
 > This is the successor for my old tool [zekroTJA/webshot](https://github.com/zekroTJA/webshot), which uses [puppeteer](https://pptr.dev).
 
 ## Usage
@@ -34,4 +34,27 @@ Options:
 You can either download the latest release builds form the [Releases page](https://github.com/shellshape/webshot/releases) or you can install it using cargo install.
 ```
 cargo install --git https://github.com/shellshape/webshot
+```
+
+## Configuration
+
+You can create a configuration to define some default parameters. The tool will look for a config file in one of the following locations.
+
+|  | Local | Home Config |
+|--|-------|-------------|
+| **Linux** | `./webshot.*` | `$HOME/.config/webshot/config.*` |
+| **Windows** | `.\webshot.*` | `%APPDATA%\webshot\config.*` |
+| **OSX** | `./webshot.*` | `$HOME/Library/Application Support/webshot/config.*` |
+
+Supported config types are the following.
+- YAML (`.yaml`)
+- TOML (`.toml`)
+- JSON (`.json`)
+
+An example config could look as following.
+
+```toml
+default_width = 1920
+default_height = 1080
+default_scale = 1.5
 ```