[readme] add nvm intro
Closes #2149.
diff --git a/README.md b/README.md
index a4b59bf..72a6b7a 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,7 @@
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
## Table of Contents
+- [About](#about)
- [Installing and Updating](#installing-and-updating)
- [Install & Update Script](#install--update-script)
- [Additional Notes](#additional-notes)
@@ -44,6 +45,9 @@
<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+## About
+nvm is a version manager for [node.js](https://nodejs.org/en/), designed to be installed per-user, and invoked per-shell. `nvm` works on any POSIX-compliant shell (sh, dash, ksh, zsh, bash), in particular on these platforms: unix, macOS, and windows WSL.
+
<a id="installation-and-update"></a>
<a id="install-script"></a>
## Installing and Updating
