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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/request-body/read-form/main.go

@@ -0,0 +1,44 @@
+// package main contains an example on how to use the ReadForm, but with the same way you can do the ReadJSON & ReadJSON
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+type Visitor struct {
+	Username string
+	Mail     string
+	Data     []string `form:"mydata"`
+}
+
+func main() {
+	app := iris.New()
+
+	// set the view html template engine
+	app.RegisterView(iris.HTML("./templates", ".html").Reload(true))
+
+	app.Get("/", func(ctx iris.Context) {
+		if err := ctx.View("form.html"); err != nil {
+			ctx.StopWithError(iris.StatusInternalServerError, err)
+			return
+		}
+	})
+
+	app.Post("/form_action", func(ctx iris.Context) {
+		visitor := Visitor{}
+		err := ctx.ReadForm(&visitor)
+		if err != nil && !iris.IsErrPath(err) /* see: https://github.com/kataras/iris/issues/1157 */ {
+			ctx.StopWithError(iris.StatusInternalServerError, err)
+			return
+		}
+
+		ctx.Writef("Visitor: %#v", visitor)
+	})
+
+	app.Post("/post_value", func(ctx iris.Context) {
+		username := ctx.PostValueDefault("Username", "iris")
+		ctx.Writef("Username: %s", username)
+	})
+
+	app.Listen(":8080")
+}