These are the two rules that are needed for that.
Code:
INSERT INTO `rule_values` (`ruleset_id`, `rule_name`, `rule_value`, `notes`) VALUES (1, 'Bots:CreationLimit', '7', '');
INSERT INTO `rule_values` (`ruleset_id`, `rule_name`, `rule_value`, `notes`) VALUES (1, 'Bots:SpawnLimit', '7', '');
Then set the number as you see fit.
Morty