Add more tutorial in the guide book#19

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kubkon wants to merge 4 commits intomasterfrom

Commits on Jan 2, 2020

Add more tutorial in the guide book
Jakub Konka
committed
Describe each Cargo depedency
Jakub Konka
committed

Commits on Jan 3, 2020

Add basics of the app's logic
Jakub Konka
committed

Commits on Jan 4, 2020

Fix compilation and refactor Cargo.toml
Jakub Konka
committed