Add documentation for #125

[znck]

@sunnylost Please add documentation for #125

[sunnylost]

I’m spending the whole September on a work project, so i maybe don't have enough time to write this, my apologies.

[sunnylost]

Holiday comes, got a little break. So where should I write this document? docs only contains 2.2 and 2.3.

[znck]

Thanks. In 2.3, I'll rename it to 2.5.