docs: Update README with setup info

Author: bencodezen

README.md

@@ -1 +1,23 @@
-# docs-next
+# Vuejs.org Docs - Next Repo
+
+This repo contains the code for the future VuePress version of the Vuejs.org docs.
+
+## Getting Setup
+
+1. Clone repository
+
+```bash
+git clone git@github.com:vuejs/docs-next.git
+```
+
+2. Install dependencies
+
+```bash
+yarn # or npm install
+```
+
+3. Start local development environment
+
+```bash
+yarn serve
+```