code: function (conn, cb) {
  
        // TODO: disconnect here
        if (typeof conn == 'function') {
          cb = conn;
          conn = null;
        }
        if (!conn) {
          connections = {};
          return cb();
        }
        if(!connections[conn]) return cb();
        delete connections[conn];
        cb();
      }
docs: Fired when a model is unregistered, typically when the server
  is killed. Useful for tearing-down remaining open connections,
  etc.
  
  @param  {Function} cb [description]
  @return {[type]}      [description]
   Teardown a Connection