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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/bootstrap/middleware/identity/identity.go

@@ -0,0 +1,33 @@
+package identity
+
+import (
+	"time"
+
+	"github.com/kataras/iris/v12"
+
+	"github.com/kataras/iris/v12/_examples/bootstrap/bootstrap"
+)
+
+// New returns a new handler which adds some headers and view data
+// describing the application, i.e the owner, the startup time.
+func New(b *bootstrap.Bootstrapper) iris.Handler {
+	return func(ctx iris.Context) {
+		// response headers
+		ctx.Header("App-Name", b.AppName)
+		ctx.Header("App-Owner", b.AppOwner)
+		ctx.Header("App-Since", time.Since(b.AppSpawnDate).String())
+
+		ctx.Header("Server", "Iris: https://iris-go.com")
+
+		// view data if ctx.View or c.Tmpl = "$page.html" will be called next.
+		ctx.ViewData("AppName", b.AppName)
+		ctx.ViewData("AppOwner", b.AppOwner)
+		ctx.Next()
+	}
+}
+
+// Configure creates a new identity middleware and registers that to the app.
+func Configure(b *bootstrap.Bootstrapper) {
+	h := New(b)
+	b.UseGlobal(h)
+}