如何使用权限表来获取Laravel 4中Sentry的动态权限

Question

I want to create dynamic permissions for each users through checkbox using Sentry in Laravel 4. I've created a table named permissions that has two columns:

id | name | user_id

Now, I want to use:

Sentry::hasAccess('any_permission_name')

But this 'any_permission_name' should come from permissions table.

I've extend the SentrUserModel in my User model and add this relation to the User model:

    public function permission(){
        return $this->hasMany('Permission');
}

Now, I don't understand how to use Sentry with different permissions table for fetching the permissions. Is there any way to use Sentry for this?