regression: css broken when loading forum in chrome
/cc @dom96 

loading https://forum.nim-lang.org/

* works with chrome incognito
* works in safari
* fails in chrome

![image](https://user-images.githubusercontent.com/2194784/47394867-4cd3db00-d6d9-11e8-876a-d84a449544c1.png)

this happened after i restarted my laptop
not sure what would be causing it; i'll try clearing cache but that's the only site for which I'm having issues

developper windows shows:
Failed to load resource: net::ERR_CONTENT_DECODING_FAILED
nimforum.css:1 