Fixed MySQL 5.7 compatibility

’’’
General error: 3065 Expression #1 of ORDER BY clause is not in SELECT list, references column information_schema.kcu.ORDINAL_POSITION
’’’

db/mysql/Schema.php

@@ -506,7 +506,8 @@ private function loadTableConstraints($tableName, $returnType)
     `kcu`.`REFERENCED_TABLE_NAME` AS `foreign_table_name`,
     `kcu`.`REFERENCED_COLUMN_NAME` AS `foreign_column_name`,
     `rc`.`UPDATE_RULE` AS `on_update`,
-    `rc`.`DELETE_RULE` AS `on_delete`
+    `rc`.`DELETE_RULE` AS `on_delete`,
+    `kcu`.`ORDINAL_POSITION` as `position`
 FROM (SELECT DATABASE() AS `name`) AS `sch`
 INNER JOIN `information_schema`.`KEY_COLUMN_USAGE` AS `kcu`
     ON `kcu`.`TABLE_SCHEMA` = COALESCE(:schemaName, `sch`.`name`) AND `kcu`.`CONSTRAINT_SCHEMA` = `kcu`.`TABLE_SCHEMA` AND `kcu`.`TABLE_NAME` = :tableName