add router group for http server (#1208)

examples/http/middlewares/main.go

@@ -30,8 +30,8 @@ func main() {
 	// add path filter to custom route
 	r.GET("/hello/{name}", sayHelloHandler, pathFilter, pathFilter2)
 
-	// add path filter to sub router
-	r2 := r.NewSubRouter("/v2", pathFilter, pathFilter2)
+	// add path filter to router group
+	r2 := r.Group("/v2", pathFilter, pathFilter2)
 	r2.GET("/say/{name}", sayHelloHandler)
 
 	app := kratos.New(

transport/http/router.go

@@ -29,8 +29,8 @@ func newRouter(prefix string, srv *Server, filters ...FilterFunc) *Router {
 	return r
 }
 
-// NewSubRouter returns a new sub router
-func (r *Router) NewSubRouter(prefix string, filters ...FilterFunc) *Router {
+// Group returns a new router group.
+func (r *Router) Group(prefix string, filters ...FilterFunc) *Router {
 	var newFilters []FilterFunc
 	newFilters = append(newFilters, r.filters...)
 	newFilters = append(newFilters, filters...)