Renamed GroupWithExisting to Group

- GroupWithExisting wa too long for a default behaviour function.
- Updated README version as this is a breaking change.

Author: joeybloggs

README.md

@@ -1,6 +1,6 @@
 ##Pure
 <img align="right" src="https://raw.githubusercontent.com/go-playground/pure/master/logo.png">
-![Project status](https://img.shields.io/badge/version-3.1.1-green.svg)
+![Project status](https://img.shields.io/badge/version-4.0.0-green.svg)
 [![Build Status](https://semaphoreci.com/api/v1/joeybloggs/pure/branches/master/badge.svg)](https://semaphoreci.com/joeybloggs/pure)
 [![Coverage Status](https://coveralls.io/repos/github/go-playground/pure/badge.svg?branch=master)](https://coveralls.io/github/go-playground/pure?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/pure)](https://goreportcard.com/report/github.com/go-playground/pure)

group.go

@@ -11,7 +11,7 @@ type IRouteGroup interface {
 	IRoutes
 	GroupWithNone(prefix string) IRouteGroup
 	GroupWithMore(prefix string, middleware ...Middleware) IRouteGroup
-	GroupWithExisting(prefix string) IRouteGroup
+	Group(prefix string) IRouteGroup
 }
 
 // IRoutes interface for routes
@@ -167,8 +167,8 @@ func (g *routeGroup) GroupWithMore(prefix string, middleware ...Middleware) IRou
 	return rg
 }
 
-// GroupWithExisting creates a new sub router with specified prefix and retains existing middleware.
-func (g *routeGroup) GroupWithExisting(prefix string) IRouteGroup {
+// Group creates a new sub router with specified prefix and retains existing middleware.
+func (g *routeGroup) Group(prefix string) IRouteGroup {
 
 	rg := &routeGroup{
 		prefix:     g.prefix + prefix,

group_test.go

@@ -46,7 +46,7 @@ func TestUseAndGroup(t *testing.T) {
 	Equal(t, body, http.MethodGet)
 	Equal(t, log, "/")
 
-	g := p.GroupWithExisting("/users")
+	g := p.Group("/users")
 	g.Get("/", fn)
 	g.Get("/list/", fn)
 
@@ -81,7 +81,7 @@ func TestUseAndGroup(t *testing.T) {
 	Equal(t, body, http.MethodGet)
 	Equal(t, log, "/superheros/list/2")
 
-	sc := sh.GroupWithExisting("/children")
+	sc := sh.Group("/children")
 	sc.Get("/", fn)
 	sc.Get("/list/", fn)