Add necessary caps to admin and editor roles to manage usergroups

edit-flow_usergroups_caps.php

add_action( 'admin_init', 'ef_usergroups_cap_fix' );

function ef_usergroups_cap_fix() {
	global $wp_roles;
	
	if ( ! isset( $wp_roles ) )
		$wp_roles = new WP_Roles();
	
	// Add necessary capabilities to allow management of usergroups and post subscriptions
	// edit_post_subscriptions - administrator + editor
	// edit_usergroups - adminstrator
	if( $wp_roles->is_role('administrator') ) {
		$admin_role =& get_role('administrator');
		$admin_role->add_cap('edit_post_subscriptions');
		$admin_role->add_cap('edit_usergroups');
	}
	if( $wp_roles->is_role('editor') ) {	
		$editor_role =& get_role('editor');
		$editor_role->add_cap('edit_post_subscriptions');
	}
}