Add Created & Updated to Milestone (#12662)

* Add Created and Updated to Milestone table and expose via API

* Expose to UI - To Overloaded ?!?

* fix unit test

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

models/migrations/v149.go

@@ -0,0 +1,25 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"fmt"
+
+	"code.gitea.io/gitea/modules/timeutil"
+
+	"xorm.io/xorm"
+)
+
+func addCreatedAndUpdatedToMilestones(x *xorm.Engine) error {
+	type Milestone struct {
+		CreatedUnix timeutil.TimeStamp `xorm:"INDEX created"`
+		UpdatedUnix timeutil.TimeStamp `xorm:"INDEX updated"`
+	}
+
+	if err := x.Sync2(new(Milestone)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+	return nil
+}