Eloquent and postgresql incrementing

It looks like is something related to Mass Assignment. How do you model looks like?

http://laravel.com/docs/4.2/eloquent#mass-assignment

That's my model :

<?php

Class EbrizMessenger extends Eloquent{

    /**
     * @var string
     */
    protected $table = 'ebrizmessenger';
    /**
     * @var string
     */

    protected $primaryKey = 'id';

    /**
     * @var bool
     */
    public $timestamps = false;
}

That's what i try to do :

$data = [
            'user_code_sender' => $this->user->user_code,
            'broadcasting_category' => $input['broadcasting_category'],
            'priority' => $input['priority'],
            'subject' => $input['subject'],
            'message' => $input['message'],
            'message_sending_date' => date("Y-m-d H:i:s"),
        ];
        if($input['broadcasting_category'] == '2')
        {
            $data['entity_id'] = $this->user->rest_entity_id;
            $data['auto_hide_datetime'] = date("Y-m-d H:i:s", strtotime("+1 week"));
        }

        if($input['broadcasting_category'] == '0')
            $data['user_code_receiver'] = $input['user_code_receiver'];

        \DB::table('ebrizmessenger')->insert($data);

Or with Eloquent :

$message = new \EbrizMessenger();
$message->user_code_sender = $this->user->user_code;
$message->broadcasting_category = $input['broadcasting_category'];

$message->priority = $input['priority'];
$message->subject = $input['subject'];
$message->message = $input['message'];
$message->message_sending_date = date("Y-m-d H:i:s");
$message->save()

Did you read the link i posted here? To be simple you need to specify fields inside model something like this:

Class EbrizMessenger extends Eloquent{
    protected $fillable = ['priority', 'subject', 'message'];
}

I have already tried :

/**
* @var array
*/
protected $guarded = array('id');

But still the same error !

Can you show me the structure of your table? With $fillable should be enough, but you need to specify fields required, obviously.