New to Angular and looking for guidance First, let me say I'm not a web developer, but I'm learning :)

I've been messing with Angular2 (off and on) for a few months now and I wanted to take on my first real project, but I'm unsure of a small piece.

I want to build a website for playing a card game (like go fish, crazy eights, war etc). Initially this will only be a 2 player game but may be extended later to accommodate more players per game.

I want to allow multiple games to be played simultaneously between pairs of players.  

The question I have is: where should I put the game logic, into the backend server, or in the angular2 frontend?

Thanx
-rx