Update README.md

Author: stipsan

README.md

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 # system-font-stack
 
+[![volkswagen status](https://auchenberg.github.io/volkswagen/volkswargen_ci.svg?v=1)](https://github.com/auchenberg/volkswagen)
+
 Use the system font family so your web app look more native
 
 Inspired by https://css-tricks.com/snippets/css/system-font-stack/