public ActivityEnvelope(ActivityViewModel model)
 {
     Activity = new Activity();
     Activity.Action = model.Activity_Action;
     Activity.Actor.Name = model.Actor_Name;
     Activity.Actor.Email = model.Actor_Email;
     Activity.Message = model.Activity_Message;
     Activity.OG_Object.Title = model.Object_Title;
     Activity.OG_Object.Url = model.Object_Url;
 }
        public async Task<ActionResult> Create(ActivityViewModel model)
        {
            ActivityEnvelope envelope = new ActivityEnvelope(model);

            if (Request.HttpMethod == "POST")
            {
                await YammerRepository.PostActivity(envelope);
                return Redirect("/");
            }
            else
            {
                return View(model);
            }
        }