I'm having difficulty figuring out how to add a date range to my report. Ideally I want the report to show all records in a 24-hour period.

This is what I have so far:

class DailyReport extends SS_Report {

    // the name of the report
    public function title() {
        return 'Auckland List';
    }

    // what we want the report to return
    public function sourceRecords($params = null) {
        return NomineeList::get()->where(array(
            '"Venue"' => 'Auckland'
        ))->sort('Shared');
    }

    function parameterFields() {
        $fields = DateField::create('Created', 'Report Day');
        return $fields;
    }

    // which fields on that object we want to show
    public function columns() {
        $fields = array(
            'RunnersFirstName' => 'First Name',
            'RunnersLastName' => 'Last Name',
            'RunnersEmail' => 'Email',
            'Address' => 'Address',
            'Message' => 'Message',
            'Name' => 'Nominated by',
            'Email' => 'Nominator\'s Email',
            'Shared' => 'Shared'
        );

        return $fields;
    }
}