docs: update toc

Author: AuHau

README.md

@@ -28,11 +28,17 @@ This package is inspired by the [go-ipfs repo migration tool](https://github.com
   - [Use in a browser with browserify, webpack or any other bundler](#use-in-a-browser-with-browserify-webpack-or-any-other-bundler)
   - [Use in a browser Using a script tag](#use-in-a-browser-using-a-script-tag)
 - [Usage](#usage)
-  - [Writing migration](#writing-migration)
-  - [Migrations matrix](#migrations-matrix)
 - [API](#api)
 - [CLI](#cli)
-- [Versioning](#versioning)
+- [Creating a new migration](#creating-a-new-migration)
+  - [Architecture of a migration](#architecture-of-a-migration)
+  - [Browser vs. NodeJS environments](#browser-vs-nodejs-environments)
+  - [Guidelines](#guidelines)
+  - [Integration with js-ipfs](#integration-with-js-ipfs)
+  - [Empty migrations](#empty-migrations)
+  - [Migrations matrix](#migrations-matrix)
+- [Developer](#developer)
+    - [Module versioning notes](#module-versioning-notes)
 - [Contribute](#contribute)
 - [License](#license)