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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/routing/subdomains/multi/main.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+func main() {
+	app := iris.New()
+
+	/*
+	 * Setup static files
+	 */
+
+	app.HandleDir("/assets", "./public/assets")
+	app.HandleDir("/upload_resources", "./public/upload_resources")
+
+	dashboard := app.Party("dashboard.")
+	{
+		dashboard.Get("/", func(ctx iris.Context) {
+			ctx.Writef("HEY FROM dashboard")
+		})
+	}
+	system := app.Party("system.")
+	{
+		system.Get("/", func(ctx iris.Context) {
+			ctx.Writef("HEY FROM system")
+		})
+	}
+
+	app.Get("/", func(ctx iris.Context) {
+		ctx.Writef("HEY FROM frontend /")
+	})
+	// http://domain.local:80
+	// http://dashboard.local
+	// http://system.local
+	// Make sure you prepend the "http" in your browser
+	// because .local is a virtual domain we think to show case you
+	// that you can declare any syntactical correct name as a subdomain in iris.
+	app.Listen("domain.local:80") // for beginners: look ../hosts file
+}