feat!: implemented multigame support (#34)

Reviewed-on: #34
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

knockoutwhistweb/app/exceptions/NotEnoughPlayersException.java

@@ -0,0 +1,7 @@
+package exceptions;
+
+public class NotEnoughPlayersException extends GameException {
+    public NotEnoughPlayersException(String message) {
+        super(message);
+    }
+}