See `discipline/666/teachers` page.

Link with name "Back to rating". The bug was caused by editing some routes.

Ternary operator is left-associated in PHP (right in C++), so we have:
    (...) ? one : second;

I have put an extra braces to improve the evaluation order.

Look at office/ page

Appears only when teacher doesn't have any disciplines.

it-lab/grade#29 (comment 111)

*move selector to the center of navbar
*modify link to the selector
*add font icon

* Integration of drag-drop zone
* Some examples about new file structure

* Integration of drag-drop zone
* Some examples about new file structure