Add persistent DB connections

Author: mintopia

config/database.php

@@ -60,6 +60,7 @@
             'engine' => null,
             'options' => extension_loaded('pdo_mysql') ? array_filter([
                 PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'),
+                PDO::ATTR_PERSISTENT => true,
             ]) : [],
         ],