code: function authenticate(req, res, next) {
    var callback = _.bind(authCallback, {req: req, res: res});
    passport.authenticate('local', callback)(req, res, next)
  }
docs: Authenticate a request and sign a token.
  @param {http.IncomingMessage} req - The request message object
  @param {http.ServerResponse} res - The outgoing response object
  @param {function} next - The next handler callback
  @return {http.ServerResponse} The result of calling the
  [callback function]{@link auth:local~authCallback}