Special CMB2 Field that allows users to define an autocomplete text field for users
$cmb2->add_field( array(
'name' => 'Author',,
'id' => 'author',
'desc' => 'Type the name of the author and select from the options',
'type' => 'user_select_text'
'options' => array(
'minimum_user_level' => 0, // Enable search for all user levels.. use with caution.
),
) );