Your query syntax is fine it's your PHP syntax that has the problem:
// Do I add the sort here ?
// like this
//Tried a couple ways it errors out, so I am sure my syntax is wrong
//$query = "select id, username, admin, offense, server from ".$table ORDER BY username;
//
$query = "select id, username, admin, offense, server from ". $table . " ORDER BY username";
In the commented code you aren't opening up your string to add the ORDER BY clause.