Allow specifying maximum connection counts per user

app/Server/Http/Controllers/Admin/StoreUsersController.php

@@ -41,6 +41,7 @@ class StoreUsersController extends AdminController
             'auth_token' => (string) Str::uuid(),
             'can_specify_subdomains' => (int) $request->get('can_specify_subdomains'),
             'can_share_tcp_ports' => (int) $request->get('can_share_tcp_ports'),
+            'max_connections' => (int) $request->get('max_connections'),
         ];
 
         $this->userRepository