Add example of primitive string substitution#496

Open

straight-shoota wants to merge 2 commits intocrystal-lang:masterfrom straight-shoota:feature/tutorial-primitive-string-substitution

+65-5

Commits on Mar 26, 2021

Add example of primitiv string substitution
straight-shoota
committed

Commits on Apr 19, 2021

Replace .not_nil! with conditional
straight-shoota
committed