docs: add max_length to sample code

Author: kenjis

user_guide_src/source/models/model/027.php

@@ -7,10 +7,10 @@
 class UserModel extends Model
 {
     protected $validationRules = [
-        'username'     => 'required|alpha_numeric_space|min_length[3]',
-        'email'        => 'required|valid_email|is_unique[users.email]',
-        'password'     => 'required|min_length[8]',
-        'pass_confirm' => 'required_with[password]|matches[password]',
+        'username'     => 'required|max_length[30]|alpha_numeric_space|min_length[3]',
+        'email'        => 'required|max_length[254]|valid_email|is_unique[users.email]',
+        'password'     => 'required|max_length[255]|min_length[8]',
+        'pass_confirm' => 'required_with[password]|max_length[255]|matches[password]',
     ];
     protected $validationMessages = [
         'email' => [

user_guide_src/source/models/model/028.php

@@ -1,6 +1,6 @@
 <?php
 
 $fieldName  = 'username';
-$fieldRules = 'required|alpha_numeric_space|min_length[3]';
+$fieldRules = 'required|max_length[30]|alpha_numeric_space|min_length[3]';
 
 $model->setValidationRule($fieldName, $fieldRules);

user_guide_src/source/models/model/029.php

@@ -1,9 +1,9 @@
 <?php
 
 $validationRules = [
-    'username' => 'required|alpha_numeric_space|min_length[3]',
+    'username' => 'required|max_length[30]|alpha_numeric_space|min_length[3]',
     'email'    => [
-        'rules'  => 'required|valid_email|is_unique[users.email]',
+        'rules'  => 'required|max_length[254]|valid_email|is_unique[users.email]',
         'errors' => [
             'required' => 'We really need your email.',
         ],