Запрос на слияние 'task' (#2) из task в master

update demo/demo.md

create README.md

upload files

create demo/demo.md

update demo/demo.md

upload files

create demo/demo.md

create dev/solution.cs

create README.md

upload files

create demo/demo.md

Запрос на слияние 'student2' (#1) из student2 в task

create dev/solution.cs

docs: add contribution variant for branch refs/heads/student2

create dev/solution.cs

create spec/codex.md