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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/view/herotemplate/app.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"bytes"
+
+	"github.com/kataras/iris/v12/_examples/response-writer/herotemplate/template"
+
+	"github.com/kataras/iris/v12"
+)
+
+// $ go get -u github.com/shiyanhui/hero/hero
+// $ go run app.go
+//
+// Read more at https://github.com/shiyanhui/hero/hero
+
+func main() {
+	app := iris.New()
+
+	app.Get("/users", func(ctx iris.Context) {
+		ctx.Gzip(true)
+		ctx.ContentType("text/html")
+
+		userList := []string{
+			"Alice",
+			"Bob",
+			"Tom",
+		}
+
+		// Had better use buffer sync.Pool.
+		// Hero(github.com/shiyanhui/hero/hero) exports GetBuffer and PutBuffer for this.
+		//
+		// buffer := hero.GetBuffer()
+		// defer hero.PutBuffer(buffer)
+		// buffer := new(bytes.Buffer)
+		// template.UserList(userList, buffer)
+		// ctx.Write(buffer.Bytes())
+
+		// using an io.Writer for automatic buffer management (i.e. hero built-in buffer pool),
+		// iris context implements the io.Writer by its ResponseWriter
+		// which is an enhanced version of the standard http.ResponseWriter
+		// but still 100% compatible, GzipResponseWriter too:
+		// _, err := template.UserListToWriter(userList, ctx.GzipResponseWriter())
+		buffer := new(bytes.Buffer)
+		template.UserList(userList, buffer)
+
+		_, err := ctx.Write(buffer.Bytes())
+		if err != nil {
+			ctx.StopWithError(iris.StatusInternalServerError, err)
+			return
+		}
+	})
+
+	app.Listen(":8080")
+}