Run in a terminal
hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0xC000000B8,"HIDKeyboardModifierMappingDst":0xC000000CD}]}'
(by @andrestaltz)
If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.