demochallenge commands.jsfg

ps-grammar/demoChallenge/commands.jsgf

@@ -4,5 +4,5 @@ public <statement> = [tobi] [please] <command> [please] [tobi];
 
 <command> = <clean> | <party>;
 <clean> = clean up | start cleaning;
-<party> = party starts | party begining;
+<party> = party starts | party beginning;