How to create custom controllers using ion auth?

[eluser]rashgang[/eluser]
Hi Everybody,

https://github.com/benedmunds/CodeIgniter-Ion-Auth

Could you please give me suggestion that i have to create site admin panel using ion auth.

my folder structure will be

controller
admin
dashboard.php
pages.php
........ etc

I am going to create many controller like this using ion auth. is it secure to check whether the user is admin or member group like this in constructor of every controller or is it wrong to check like this and also can we rename auth to admin?

if (!$this->ion_auth->is_admin()) {

redirect('home');
}

Please advise on this