add live demo link to readme (FormidableLabs#677)

Author: Kate Schaefer

README.md

@@ -8,6 +8,8 @@ ReactJS based Presentation Library
 [Spectacle Boilerplate MDX](https://github.com/FormidableLabs/spectacle-boilerplate-mdx/)
 [Spectacle Boilerplate](https://github.com/FormidableLabs/spectacle-boilerplate/)
 
+Looking for a quick preview of what you can do with Spectacle? Check out our live Demo Deck [here](https://raw.githack.com/FormidableLabs/spectacle/master/one-page.html#/).
+
 Have a question about Spectacle? Submit an issue in this repository using the "Question" template.
 
 ## Contents