router.go
func (r *Router) Options(pattern string, handlers ...interface{}) *Router {
	c := r.pattern(pattern)
	c.Method = "OPTIONS"
	clone := r.clone(c)
	clone.handle(handlers)
	return clone
}
func (r *Router) Options(pattern string, handlers ...interface{}) *Router {
	c := r.pattern(pattern)
	c.Method = "OPTIONS"
	clone := r.clone(c)
	clone.handle(handlers)
	return clone
}
// Options handles OPTIONS methods with a given pattern