Implemented basic recruiting

sql/create_database_structure.sql

@@ -51,5 +51,7 @@ CREATE TABLE IF NOT EXISTS profiles (
 	spies INTEGER DEFAULT 0,
 	scientists INTEGER DEFAULT 0,
 
+	lastRecruitTime TIMESTAMP DEFAULT '2019-01-01 00:00:00',
+
 	CONSTRAINT FOREIGN KEY fk_accountId(accountId) REFERENCES accounts(id) ON UPDATE CASCADE ON DELETE CASCADE
 );