Update README.md

Author: mco-gh

README.md

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 # Tools for authoring and serving codelabs
 
-[![Demo](https://storage.googleapis.com/claat/demo.png)](https://storage.googleapis.com/claat/demo.mp4)
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 Codelabs are interactive instructional tutorials, which can be authored in Google Docs
 using some simple formatting conventions. You can also author codelabs using markdown syntax.
 This repo contains all the tools and documentation you’ll need for building and publishing