##  app/controllers/components/auth.php
<?php

class AuthComponent extends Object
{

    /* Component config variables */
    var $user_model = "User";
    var $group_model = "Group";
    var $user_fields = array('id' => 'id', 'username' => 'username', 'password' => 'password');
    var $group_fields = array('id' => 'id', 'name' => 'name');
    var $components = array('Session');
    var $login_page = '/users/login'; // login action
    var $logout_page = '/'; // Page to redirect to when user logs out
    var $deny_page = '/users/denied'; // Page to redirect if you deny access but don't want take user to login page
    var $sesskey = "User";

    /* Don't modify these variables */
    var $last_page = null;
    var $user = null;
    var $controller;

    function startup(&$controller)
    {
        $this->controller = $controller;
        if ($this->Session->valid() &&  $this->Session->check($this->sesskey))
        {
            $this->user = $this->Session->read($this->sesskey);
        }
        $this->controller->set('Auth', $this->user);
    }

    // Method to check if user is logged.
    function login($data)
    {
        $username = $data[$this->user_fields['username']];
        $password = $data[$this->user_fields['password']];
        $conditions = array(
          $this->user_model.".".$this->user_fields['username'] => $username,
          $this->user_model.".".$this->user_fields['password'] => md5($password),
          $this->user_model.".active" => 1
        );
        $user = $this->controller->{$this->user_model}->find($conditions);

        if (empty($user)) {
            return false;
        } else {
            $sessdata["{$this->user_model}"]['id']         = $user["{$this->user_model}"]["{$this->user_fields['id']}"];
            $sessdata["{$this->user_model}"]['username']   = $user["{$this->user_model}"]["{$this->user_fields['username']}"];
            $sessdata["{$this->user_model}"]['password']   = $user["{$this->user_model}"]["{$this->user_fields['password']}"];
            $sessdata["{$this->user_model}"]['groups']     = array();

            if (!empty($user["{$this->group_model}"]))
            {
              foreach($user["{$this->group_model}"] as $group)
              {
                array_push($sessdata["{$this->user_model}"]['groups'], $group['name']);
              }
            }

            $sessdata["{$this->user_model}"]['login_hash'] = md5($this->sesskey . $sessdata["{$this->user_model}"]['username'] . $sessdata["{$this->user_model}"]['password']);
            $this->Session->write($this->sesskey, $sessdata);
            return true;
        }
    }

    // Logout user and destroy cookie
    function logout($redirect=null)
    {
        $this->user = null;
        $this->Session->delete($this->sesskey);
        $page = (!empty($redirect)) ? $redirect : $this->logout_page;
        $this->controller->redirect($page);
    }

    // Check is user is part of usergroup specified
    function permit($groups=null, $redirect=null)
    {
        $hasAccess = false;
        // User page tracker
        if ($this->controller->action != "login")
        {
          $this->last_page = $this->controller->here;
        }

        $sessdata = $this->Session->read($this->sesskey);

        # logged in...
        if (!empty($this->user))
        {
          # you got some groups...
          if (!empty($groups))
          {
              foreach ($groups as $group)
              {
                # and any group name matches the provided name...
                if (array_search($group, $sessdata["{$this->user_model}"]['groups']) === false)
                {
                }
                else
                {
                  $hasAccess = true;
                }
              }
          }
          else
          {
            $hasAccess = false;
          }
        }

        if(!$hasAccess)
        {
            $page = (!empty($redirect)) ? $redirect : $this->login_page;
            $this->controller->redirect($page);
        }

    }

    function deny($redirect=null)
    {
        $page = (!empty($redirect)) ? $redirect : $this->deny_page;
        $this->controller->redirect($page);
    }

}

?>
## app/views/helpers/auth.php
<?php
class AuthHelper extends Helper
{
  var $helpers = array('Html','Session');

  # Returns true/false if the current user is logged in.
  function loggedIn()
  {
    return $this->Session->read('User') ? true : false;
  }

  # Returns true/false if current user is member of specific group.
  function hasRole($role = '')
  {
    if($user = $this->Session->read('User'))
    {
      return in_array($role, $user['User']['groups']) ? true : false;
    }
    return false;
  }

}
?>

## app/views/users/login.ctp
<h1>Member Login</h1>
<?php echo $form->create('User', array('action' => 'login')) ?>
<fieldset>
    <legend>User Login</legend>

    <?php echo $form->input('User.username', array('label' => 'Username: ', 'style' => 'width: 150px'))?><br />

    <label for="password">Password: </label>
    <?php echo $form->password('User.password', array('style' => 'width: 150px'))?><br />

    <label for="submit"> </label><br />
    <?php echo $form->submit('Sign In')?>
</fieldset>
</form>

## app/controllers/users_controller.php
<?php
class UsersController extends AppController {
  var $uses = array('User','Group');

	function login()
	{
   if(isset($this->data['User']))
     {
       if($this->Auth->login($this->data['User']))
       {
         $this->redirect('/');
       }
       $this->flash("Invalid login", 'login');
     }
	}

	function logout()
	{
		$this->Auth->logout();
		$this->flash("You have been logged out.", '/');
	}

}
?>

## app/models/user.rb
<?php
class User extends AppModel
{
  var $hasAndBelongsToMany = array(
    'Group' => array(
      'className'  => 'Group',
      'joinTable'  => 'groups_users',
      'foreignKey' => 'user_id',
      'order'      => 'Group.name DESC'
    )
  );
}
?>

## app/models/group.rb
<?php

class Group extends AppModel
{
    var $hasAndBelongsToMany = array(
      'User' => array(
        'className'   => 'User',
        'joinTable'   => 'groups_users',
        'foreignKey'  => 'user_id',
        'uniq'        => true,
        'order' => 'User.username DESC'
      )
    );
}

?>

## migrations (SQL)
CREATE TABLE users (
  id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
  username varchar(50) NOT NULL default '',
  password varchar(32) NOT NULL default '',
  fname varchar(50) NOT NULL,
  lname varchar(50) NOT NULL,
	phone varchar(32) default '',
  email varchar(100) NOT NULL default '',
  active tinyint(1) unsigned NOT NULL default '0',
  created datetime NOT NULL default '0000-00-00 00:00:00',
  modified datetime NOT NULL default '0000-00-00 00:00:00'
) ENGINE=InnoDB;

CREATE TABLE groups (
	id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
  name varchar(50) NOT NULL default '',
  created datetime NOT NULL default '0000-00-00 00:00:00',
  modified datetime NOT NULL default '0000-00-00 00:00:00'
) ENGINE=InnoDB;

CREATE TABLE groups_users (
  user_id INT UNSIGNED NOT NULL,
  group_id INT UNSIGNED NOT NULL,
  created datetime NOT NULL default '0000-00-00 00:00:00',
  modified datetime NOT NULL default '0000-00-00 00:00:00'
) ENGINE=InnoDB;

# passwords are 'test'
INSERT INTO `users` (`id`, `username`, `password` , `fname`, `lname`, `email`, `active`, `created`, `modified`) VALUES (1, 'admin', '098f6bcd4621d373cade4e832627b4f6', 'System', 'Administrator', 'admin@pitsparanormal.com', 1, '0000-00-00 00:00:00', '0000-00-00 00:00:00');
INSERT INTO `users` (`id`, `username`, `password` , `fname`, `lname`, `email`, `active`, `created`, `modified`) VALUES (2, 'member', '098f6bcd4621d373cade4e832627b4f6', 'PITS', 'Member', 'member@pitsparanormal.com', 1,  '0000-00-00 00:00:00', '0000-00-00 00:00:00');

INSERT INTO `groups` (`id`, `name`, `created`, `modified`) VALUES (1, 'Member', '0000-00-00 00:00:00', '0000-00-00 00:00:00');
INSERT INTO `groups` (`id`, `name`, `created`, `modified`) VALUES (2, 'Admin', '0000-00-00 00:00:00', '0000-00-00 00:00:00');

INSERT INTO `groups_users` (`user_id`, `group_id`) VALUES (1,2);
INSERT INTO `groups_users` (`user_id`, `group_id`) VALUES (2,1);