Permission.php

<?php 

use Phalcon\Mvc\Dispatcher,
    Phalcon\Events\Event;


class Permission extends \Phalcon\Mvc\User\Plugin
{
    /**
    * Constants to prevent typo
    */
    const GUEST = 'guest';
    const USER = 'user';
    const ADMIN = 'admin';
       
    protected $_publicResources =  [
        'index' => '*',
        'signin' => '*'
    ];
    
    protected $_userResources =[
        'dashboard' => ['*']
    ];
    
    protected $_adminResources = [
        'admin' => ['*']
    ];
    
    public function _getAcl()
    {   
        if(!isset($this->persistent->acl))
        {
            $acl = new \Phalcon\Acl\Adapter\Memory();
            $acl->setDefaultAction(Phalcon\Acl::DENY);
            
            $roles = [
                self::GUEST => new \Phalcon\Acl\Role(self::GUEST),
                self::USER => new \Phalcon\Acl\Role(self::USER),
                self::ADMIN => new \Phalcon\Acl\Role(self::ADMIN),
            ];
            
            foreach ($roles as $role) {
                $acl->addRole($role);
            }
            
            //Public Resources
            foreach ($this->_publicResources as $resource => $actions) {
                $acl->addResource(new \Phalcon\Acl\Resource($resource), $actions);
            }
            
            //User Resources
            foreach ($this->_userResources as $resource => $actions) {
                $acl->addResource(new \Phalcon\Acl\Resource($resource), $actions);
            }

            //Admin Resources
            foreach ($this->_adminResources as $resource => $actions) {
                $acl->addResource(new \Phalcon\Acl\Resource($resource), $actions);
            }
            
            //Allow All Roles to access the public Resources
            foreach ($roles as $role) {
                foreach($this->_publicResources as $resource => $actions) {
                    $acl->allow($role->getName(), $resource, '*');
                }
            }   
            
            //Allow User & Admin to access the User Resources
            foreach ($this->_userResources as $resource => $actions )  {
                foreach ($actions as $action) {
                    $acl->allow(self::USER, $resource, $action);
                    $acl->allow(self::ADMIN, $resource, $action);
                }
            }
            
            //Allow Admin to access the Admin Resources
           foreach ($this->_adminResources as $resource => $actions )  {
                foreach ($actions as $action) {
                    $acl->allow(self::ADMIN, $resource, $action);
                }
            }           
                        
        }
        
        return $this->persistent->acl;
    }
    
    public function beforeExecuteRoute( Event $event,  Dispatcher $dispatcher)
    {
        $role = $this->session->get('role');
        if(!$role) {
            $role = self::GUEST;
        }
        
        //Get the current controller/action from dispatcher
        $controller = $dispatcher->getControllerName();
        $action     = $dispatcher->getActionName();
        
        //Get the ACL Rule List
        $acl = $this->_getAcl();
        
        //See if they have permission
        $allowed = $acl->isAllowed($role, $controller, $action);

        if ($allowed != Phalcon\Acl::ALLOW) 
        {
            $dispatcher->forward([
                'controller' => 'index',
                'action' => 'index'
            ]);
            
            //Stop the dispatcher at the current operation
            return false;
        }
    }
    
}

return $acl;
instead of
return $this->persistent->acl;