MAPG-235 added time limit type field to the challenge

database/migrations/structure/20210510_2000_challenge.sql

@@ -2,6 +2,7 @@ CREATE TABLE `challenges` (
   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
   `token` int(10) unsigned NOT NULL,
   `time_limit` int(10) unsigned,
+  `time_limit_type` enum('game', 'round') NOT NULL DEFAULT 'game',
   `no_move` tinyint(1) NOT NULL DEFAULT 0,
   `no_pan` tinyint(1) NOT NULL DEFAULT 0,
   `no_zoom` tinyint(1) NOT NULL DEFAULT 0,