Adds docs landing page as a scaffold

docs/index.md

@@ -0,0 +1,28 @@
+## What is Rendertron?
+
+> Rendertron is a headless Chrome rendering solution designed to render & serialise web pages on the fly.
+
+- :hammer: Built with [Puppeteer](https://github.com/GoogleChrome/puppeteer)
+- :cloud: Easy deployment to Google Cloud
+- :mag: Improves SEO
+
+Rendertron is designed to enable your Progressive Web App (PWA) to serve the correct
+content to any bot that doesn't render or execute JavaScript. Rendertron runs as a
+standalone HTTP server. Rendertron renders requested pages using Headless Chrome,
+[auto-detecting](#auto-detecting-loading-function) when your PWA has completed loading
+and serializes the response back to the original request. To use Rendertron, your application
+configures [middleware](#middleware) to determine whether to proxy a request to Rendertron.
+Rendertron is compatible with all client side technologies, including [web components](#web-components).
+
+## Demo endpoint
+
+A demo Rendertron service is available at https://render-tron.appspot.com/. It is not designed
+to be used as a production endpoint. You can use it, but there are no uptime guarantees.
+
+## Learn more
+
+- [Rendertron user guide](users-guide)
+- [Configuring Rendertron](configure)
+- [Deploying Rendertron](deploy)
+- [Best practices](best_practices)
+- [Contributing to Rendertron](contributing)