How to Add Underline button to the TinyMCE editor toolbar?

 
    add_filter( 'submit_job_form_wp_editor_args', 'customize_editor_toolbar' );

    function customize_editor_toolbar( $args ) {
	$args['tinymce']['toolbar1'] = 'bold,italic,underline,|,bullist,numlist,|,link,unlink,|,undo,redo';
	return $args;
    }