update dev/solution.cs

delete CONTRIBUTING.md

Запрос на слияние 'vetko' (#3) из vetko в master

update dеv/sоlutіоn.сs

update README.md

update dеmо/art.md

create dеv/sоlutіоn.сs

update dev/solution.cs

create Dev/solution.cs

update README.md

delete dеv/sоlutіоn.сs

update README.md

update README.md

update README.md

update readme.md

delete .gitignore