There is a problem at the standard (STL) realization: it doesn't work with assoc arrays, so [0 => 123, 5 => 123] is transformed into [0 => 123, 1 => 123].

`Arr::shuffle_assoc` saves keys.

* Fixed bug with students search
* Documentation for Model_Student
* Utility function Arr::groupBy()

You can scroll them either with mouse wheel, or by pressing <> buttons. I have set parsing from "updates.md" — it's a markdown file, where ---- is a separator for news.