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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/mvc/login-mvc-single-responsibility/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"time"
+
+	"github.com/kataras/iris/v12/_examples/mvc/login-mvc-single-responsibility/user"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/mvc"
+	"github.com/kataras/iris/v12/sessions"
+)
+
+func main() {
+	app := iris.New()
+	// You got full debug messages, useful when using MVC and you want to make
+	// sure that your code is aligned with the Iris' MVC Architecture.
+	app.Logger().SetLevel("debug")
+
+	app.RegisterView(iris.HTML("./views", ".html").Layout("shared/layout.html"))
+
+	app.HandleDir("/public", "./public")
+
+	userRouter := app.Party("/user")
+	{
+		manager := sessions.New(sessions.Config{
+			Cookie:  "sessioncookiename",
+			Expires: 24 * time.Hour,
+		})
+		userRouter.Use(manager.Handler())
+		mvc.Configure(userRouter, configureUserMVC)
+	}
+
+	// http://localhost:8080/user/register
+	// http://localhost:8080/user/login
+	// http://localhost:8080/user/me
+	// http://localhost:8080/user/logout
+	// http://localhost:8080/user/1
+	app.Listen(":8080", configure)
+}
+
+func configureUserMVC(userApp *mvc.Application) {
+	userApp.Register(
+		user.NewDataSource(),
+	)
+	userApp.Handle(new(user.Controller))
+}
+
+func configure(app *iris.Application) {
+	app.Configure(
+		iris.WithOptimizations,
+		iris.WithFireMethodNotAllowed,
+		iris.WithLowercaseRouting,
+		iris.WithPathIntelligence,
+		iris.WithTunneling,
+	)
+}