Adds creator as a tournament filter

tournaments/admin.py

@@ -42,7 +42,7 @@ class EventAdmin(admin.ModelAdmin):
 
 class TournamentAdmin(admin.ModelAdmin):
     list_display = ['display_name', 'event', 'is_private', 'start_date', 'payment', 'is_canceled']
-    list_filter = ['is_deleted']
+    list_filter = ['is_deleted', 'event__creator']
 
 class TeamRegistrationAdmin(admin.ModelAdmin):
     list_display = ['player_names', 'group_stage_position', 'name', 'tournament']