code.php

<?php

        public function populateDefaults() {
                parent::populateDefaults();

                if(!isset($this->Date) || $this->Date === null) {
                        $this->Date = SS_Datetime::now()->Format('Y-m-d H:i:s');
                }
        }

        public function getCMSFields() {
                $fields = parent::getCMSFields();

                $fields->addFieldToTab('Root.Main', $dateTimeField = new DatetimeField('Date'), 'Content');
                $dateTimeField->getDateField()->setConfig('showcalendar', true);

                $categories = NewsCategory::get()->sort('Title ASC');
                if ($categories && $categories->exists()) {
                        $fields->addFieldToTab('Root.Main', new DropdownField('CategoryID', 'Category', $categories->map()), 'Content');
                }

                $fields->addFieldToTab('Root.Main', new TextareaField('Abstract'), 'Content');

                return $fields;
        }