chore: add readme

Author: 43081j

.gitignore

@@ -0,0 +1,2 @@
+/node_modules
+*.swp

README.md

@@ -0,0 +1,30 @@
+# `@cjs-bundle/*`
+
+This repo holds the scripts for building NPM packages as commonjs bundles.
+
+As packages modernise, they are migrating to
+[ES modules](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules).
+In many cases, they choose to no longer offer (and therefore maintain) a common
+JS entrypoint.
+
+In an ideal world, everyone would move to ES modules and all would be well.
+However, not everyone has the time or priority yet to do such a migration (and
+it often isn't a small job).
+
+The job of this repository is to create common JS bundles of those "ESM-only"
+packages so you can still upgrade for whatever reason, without having to
+migrate yet.
+
+# Usage
+
+Find a supported package and install the `cjs-bundle` version like so:
+
+```sh
+npm i -D @cjs-bundle/chai
+```
+
+# Supported packages
+
+This is a list of all packages we provide legacy common JS bundles for.
+
+N/A