Add gzip task for production, fixes #712

[fhemberger]

Ref: #712
/cc @jbergstroem

[jbergstroem]

That was quick! LGTM (haven't tested but flags and formats looks good to me); here are the content types we (would) gzip, so it should match well: gzip_types text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript;

[fhemberger]

@jbergstroem You don't gzip text/html?

[jbergstroem]

@fhemberger from nginx manual: "Responses with the “text/html” type are always compressed."

[fhemberger]

@jbergstroem Ah, ok. Merging this now.

[jbergstroem]

Cool. Does this mean that it'll be shipped with next version of docs/website?

[fhemberger]

I guess all that's left to do is replacing the line here (https://github.com/nodejs/build/blob/master/setup/www/resources/scripts/build-site.sh#L28):

-  build_cmd="npm run build"
+  build_cmd="npm run build; npm run gzip"

[jbergstroem]

Ok. Want to PR?

[fhemberger]

@jbergstroem nodejs/build#405