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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

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

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+func newApp() *iris.Application {
+	app := iris.New()
+	app.Post("/", handler)
+
+	return app
+}
+
+// simple yaml stuff, read more at https://yaml.org/start.html
+type product struct {
+	Invoice  int     `yaml:"invoice"`
+	Tax      float32 `yaml:"tax"`
+	Total    float32 `yaml:"total"`
+	Comments string  `yaml:"comments"`
+}
+
+func handler(ctx iris.Context) {
+	var p product
+	if err := ctx.ReadYAML(&p); err != nil {
+		ctx.StopWithError(iris.StatusBadRequest, err)
+		return
+	}
+
+	ctx.Writef("Received: %#+v", p)
+}
+
+func main() {
+	app := newApp()
+	app.Listen(":8080")
+}