Magento – Magento 2 Add new field to Magento_User admin form

I am looking for a good approach with add/update already prepared (by default) Magento User's (module-user) form. The form can be reached in admin panel by this path:

System > All users > [chosen_user] > User's main edit tab (Account Information)

Now I'm trying with using di.xml in my custom module where I specify dependencies:
`

<preference for="Magento\User\Block\User\Edit\Tab\Main" type="Vendor_Name\Module_Name\Block\User\Edit\Tab\Main" />
<preference for="Magento\User\Block\Role\Grid\User" type="Vendor_Name\Module_Name\Block\Role\Grid\User" />

`

This is content that I've already made for a Main.php class

// @codingStandardsIgnoreFile

namespace Vendor_Name\Module_Name\Block\User\Edit\Tab;

use \Magento\User\Block\User\Edit\Tab\Main as UserEditMainTab;
use \Magento\Backend\Block\Template\Context;
use \Magento\Framework\Registry;
use \Magento\Framework\Data\FormFactory;
use \Magento\Backend\Model\Auth\Session;
use \Magento\Framework\Locale\ListsInterface;

class Main extends UserEditMainTab
{
    public function __construct(
        Context $context,
        Registry $registry,
        FormFactory $formFactory,
        Session $authSession,
        ListsInterface $localeLists,
        array $data = []
    ) {
        parent::__construct($context, $registry, $formFactory, $authSession, $localeLists, $data);
    }

    protected function _prepareForm()
    {
        /** @var $model \Magento\User\Model\User */
        $model = $this->_coreRegistry->registry('permissions_user');

        /** @var \Magento\Framework\Data\Form $form */
        $form = $this->_formFactory->create();
        $form->setHtmlIdPrefix('user_');

        $baseFieldset = $form->addFieldset('base_fieldset', ['legend' => __('Account Information __ TEST')]);

        if ($model->getUserId()) {
            $baseFieldset->addField('user_id', 'hidden', ['name' => 'user_id']);
        } else {
            if (!$model->hasData('is_active')) {
                $model->setIsActive(1);
            }
        }

        $baseFieldset->addField(
            'user_image',
            'image',
            [
                'name' => 'user_image',
                'label' => __('User Image'),
                'id' => 'user_image',
                'title' => __('User Image'),
                'required' => false,
                'note' => 'Allow image type: jpg, jpeg, png'
            ]
        );

        $baseFieldset->addField(
            'username',
            'text',
            [
                'name' => 'username',
                'label' => __('User Name'),
                'id' => 'username',
                'title' => __('User Name'),
                'required' => true
            ]
        );

        $baseFieldset->addField(
            'firstname',
            'text',
            [
                'name' => 'firstname',
                'label' => __('First Name'),
                'id' => 'firstname',
                'title' => __('First Name'),
                'required' => true
            ]
        );

        $baseFieldset->addField(
            'lastname',
            'text',
            [
                'name' => 'lastname',
                'label' => __('Last Name'),
                'id' => 'lastname',
                'title' => __('Last Name'),
                'required' => true
            ]
        );

        $baseFieldset->addField(
            'email',
            'text',
            [
                'name' => 'email',
                'label' => __('Email'),
                'id' => 'customer_email',
                'title' => __('User Email'),
                'class' => 'required-entry validate-email',
                'required' => true
            ]
        );

        $isNewObject = $model->isObjectNew();
        if ($isNewObject) {
            $passwordLabel = __('Password');
        } else {
            $passwordLabel = __('New Password');
        }
        $confirmationLabel = __('Password Confirmation');
        $this->_addPasswordFields($baseFieldset, $passwordLabel, $confirmationLabel, $isNewObject);

        $baseFieldset->addField(
            'interface_locale',
            'select',
            [
                'name' => 'interface_locale',
                'label' => __('Interface Locale'),
                'title' => __('Interface Locale'),
                'values' => $this->_LocaleLists->getTranslatedOptionLocales(),
                'class' => 'select'
            ]
        );

        if ($this->_authSession->getUser()->getId() != $model->getUserId()) {
            $baseFieldset->addField(
                'is_active',
                'select',
                [
                    'name' => 'is_active',
                    'label' => __('This account is'),
                    'id' => 'is_active',
                    'title' => __('Account Status'),
                    'class' => 'input-select',
                    'options' => ['1' => __('Active'), '0' => __('Inactive')]
                ]
            );
        }

        $baseFieldset->addField('user_roles', 'hidden', ['name' => 'user_roles', 'id' => '_user_roles']);

        $currentUserVerificationFieldset = $form->addFieldset(
            'current_user_verification_fieldset',
            ['legend' => __('Current User Identity Verification')]
        );
        $currentUserVerificationFieldset->addField(
            self::CURRENT_USER_PASSWORD_FIELD,
            'password',
            [
                'name' => self::CURRENT_USER_PASSWORD_FIELD,
                'label' => __('Your Password'),
                'id' => self::CURRENT_USER_PASSWORD_FIELD,
                'title' => __('Your Password'),
                'class' => 'input-text validate-current-password required-entry',
                'required' => true
            ]
        );

        $data = $model->getData();
        unset($data['password']);
        unset($data[self::CURRENT_USER_PASSWORD_FIELD]);
        $form->setValues($data);

        $this->setForm($form);

        return parent::_prepareForm();
    }
}

and some code for User.php

namespace Vendor_Name\Module_Name\Block\Role\Grid;

use \Magento\User\Block\Role\Grid\User as RoleGridUser;
use \Magento\Backend\Block\Widget\Grid\Extended as ExtendedGrid;

class User extends RoleGridUser
{
    protected function _prepareColumns()
    {
        parent::_prepareCollection();

        $this->addColumn(
            'user_image',
            [
                'header' => __('User Image'),
                'width' => 5,
                'align' => 'left',
                'sortable' => true,
                'index' => 'user_image'
            ]
        );

        return ExtendedGrid::_prepareCollection();
    }
}

If you take a look closer you already now that I'm trying to add a field with user's image.

Unfortunately, I don't see any changes in admin front. Of course, the needed column was added by InstallSchema script earlier to 'admin_user' table.

Contents of directories in a tree-like format:

Module_Name
├── Block
│   ├── Catalog
│   │   └── Product
│   │       └── RelatedPosts.php
│   ├── Role
│   │   └── Grid
│   │       └── User.php
│   └── User
│       └── Edit
│           └── Tab
│               └── Main.php
├── composer.json
├── etc
│   ├── di.xml
│   └── module.xml
├── Setup
    └── InstallSchema.php

What Did I do Wrong?