add a simple example about registering middleware(s) to an mvc Application

Former-commit-id: 59da5e241e1488b6b39d2ec0e72c45ad2cc7d901

_examples/mvc/middleware/main.go

@@ -0,0 +1,45 @@
+// Package main shows how you can add middleware to an mvc Application, simply
+// by using its `Router` which is a sub router(an iris.Party) of the main iris app.
+package main
+
+import (
+	"time"
+
+	"github.com/kataras/iris"
+	"github.com/kataras/iris/cache"
+	"github.com/kataras/iris/mvc"
+)
+
+var cacheHandler = cache.Handler(10 * time.Second)
+
+func main() {
+	app := iris.New()
+	mvc.Configure(app, configure)
+
+	// http://localhost:8080
+	// http://localhost:8080/other
+	//
+	// refresh every 10 second and you'll see different time output.
+	app.Run(iris.Addr(":8080"))
+}
+
+func configure(m *mvc.Application) {
+	m.Router.Use(cacheHandler)
+	m.Handle(&exampleController{
+		timeFormat: "Mon, Jan 02 2006 15:04:05",
+	})
+}
+
+type exampleController struct {
+	timeFormat string
+}
+
+func (c *exampleController) Get() string {
+	now := time.Now().Format(c.timeFormat)
+	return "last time executed without cache: " + now
+}
+
+func (c *exampleController) GetOther() string {
+	now := time.Now().Format(c.timeFormat)
+	return "/other: " + now
+}