<?php

defined('TYPO3') or die();

$colorField = [
    'exclude' => true,
    'label' => 'Color',
    'config' => [
        'type' => 'select',
        'renderType' => 'selectSingle',
        'itemsProcFunc' => 'Zab\\ZabSite\\Utility\\ContentOptions->getColors',
        'items' => [
            ['label' => 'None', 'value' => ''],
            ['label' => 'Gray', 'value' => 'black20'],
        ],
    ],
];

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns('sys_category', ['color' => $colorField]);

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes(
    'sys_category',
    'color',
    '',
    'after:title'
);