how to add the auto generated number in suitecrm

Some times we need to have auto generated increment numbers in list of records in suitecrm.
Here is the simple ready to go code, already tested.
Just write these line of arrays in

html/modules/Tasks/vardefs.php

$dictionary['Task']['fields']['tasks_id'] =array(
    'name' => 'tasks_id',
    'vname' => 'ID',
    'type' => 'int',
    'auto_increment' => true,
    'readonly' => true,
    'required' => true,
    'unified_search' => true,
    'full_text_search' => array('enabled' => true, 'boost' => 3),
    'disable_num_format' => true,
    'enable_range_search' => true,
    'options' => 'numeric_range_search_dom',
);
$dictionary['Task']['indices'][] =
    array(
        'name' => 'tasks_id',
        'type' => 'unique',
        'fields' => array('tasks_id')
    );