Part four#8

Open

oleksiipet wants to merge 7 commits intohyperskill:masterfrom

oleksiipet:part-four

Commits on Nov 24, 2018

First phase implementation done
opetenko
committed

Commits on Nov 26, 2018

Second phase implementation done
opetenko
committed

Commits on Dec 2, 2018

Second phase implementation done
opetenko
committed

Commits on Dec 8, 2018

Third phase implementation done
opetenko
committed

Commits on Dec 9, 2018

Fourth phase implementation done
opetenko
committed

Commits on Dec 18, 2018

fourth phase implementation done
opetenko
committed

Commits on Dec 29, 2018

fourth phase implementation done code review
opetenko
committed