reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/routing/sitemap/main.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"time"
+
+	"github.com/kataras/iris/v12"
+)
+
+const startURL = "http://localhost:8080"
+
+func main() {
+	app := newApp()
+
+	// http://localhost:8080/sitemap.xml
+	// Lists only online GET static routes.
+	//
+	// Reference: https://www.sitemaps.org/protocol.html
+	app.Listen(":8080", iris.WithSitemap(startURL))
+}
+
+func newApp() *iris.Application {
+	app := iris.New()
+	app.Logger().SetLevel("debug")
+
+	lastModified, _ := time.Parse("2006-01-02T15:04:05-07:00", "2019-12-13T21:50:33+02:00")
+	app.Get("/home", handler).SetLastMod(lastModified).SetChangeFreq("hourly").SetPriority(1)
+	app.Get("/articles", handler).SetChangeFreq("daily")
+	app.Get("/path1", handler)
+	app.Get("/path2", handler)
+
+	app.Post("/this-should-not-be-listed", handler)
+	app.Get("/this/{myparam}/should/not/be/listed", handler)
+	app.Get("/this-should-not-be-listed-offline", handler).SetStatusOffline()
+
+	return app
+}
+
+func handler(ctx iris.Context) { ctx.WriteString(ctx.Path()) }