Add More Examples & Categorized in Folders & TOC

Former-commit-id: ce4d711a75a4ba08ffab075e6baa88724725885b

_examples/examples/beginner/file-server/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"gopkg.in/kataras/iris.v6"
+	"gopkg.in/kataras/iris.v6/adaptors/httprouter"
+)
+
+func main() {
+	app := iris.New()
+	app.Adapt(httprouter.New())
+	// first parameter is the request path
+	// second is the operating system directory
+	app.StaticWeb("/static", "./assets")
+
+	app.Listen(":8080")
+}