jwtmiddleware.go
func FromParameter(param string) TokenExtractor {
	return func(r *http.Request) (string, error) {
		return r.URL.Query().Get(param), nil
	}
}
func FromParameter(param string) TokenExtractor {
	return func(r *http.Request) (string, error) {
		return r.URL.Query().Get(param), nil
	}
}
// FromParameter returns a function that extracts the token from the specified
// query string parameter