updated README with table of contents

Author: shadowy-pycoder

README.md

@@ -7,6 +7,20 @@
 ![GitHub Release](https://img.shields.io/github/v/release/shadowy-pycoder/go-http-proxy-to-socks)
 ![GitHub Downloads (all assets, all releases)](https://img.shields.io/github/downloads/shadowy-pycoder/go-http-proxy-to-socks/total)
 
+## Table of contents
+
+- [Introduction](#introduction)
+- [Features](#features)
+- [Installation](#installation)
+- [Usage](#usage)
+  - [Configuration via CLI flags](#configuration-via-cli-flags)
+  - [Configuration via YAML file](#configuration-via-yaml-file)
+- [Transparent proxy](#usage)
+  - [redirect (via NAT and SO_ORIGINAL_DST)](#redirect-via-nat-and-so_original_dst)
+  - [tproxy (via MANGLE and IP_TRANSPARENT)](#tproxy-via-mangle-and-ip_transparent)
+- [Links](#links)
+- [License](#license)
+
 ## Introduction
 
 `GoHPTS` CLI tool is a bridge between HTTP clients and a SOCKS5 proxy server or multiple servers (chain). It listens locally as an HTTP proxy, accepts standard HTTP