complete translation page-visibility (Second Edition) in Korean

dear translators.

I've now completed translation page-visibility (Second Edition) in to
Korean. would you mind adding it to the database?

[page visibility (second edition) : http://www.w3.org/TR/page-visibility/]
[페이지 가시성 (세컨드 에디션) : http://techhtml.github.io/page-visibility/]

Thanks.