public async Task<ActionResult> DeleteConfirmed(RolesAdminDeleteViewModel model)
 {
     if (ModelState.IsValid)
     {
         if(model.RoleId==null)
         {
             return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
         }
         var role = await RoleManager.FindByIdAsync(model.RoleId);
         var result = await RoleManager.DeleteAsync(role);
         if(!result.Succeeded)
         {
             ModelState.AddModelError("", result.Errors.First().ToString());
             return View();
         }
         
         return RedirectToAction("Index");
     }
     else
     {
         return View();
     }
 }
        //Get: /RolesAdmin/Delete/5
        public async Task<ActionResult> Delete(string id)
        {
            if(id==null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            var role=await RoleManager.FindByIdAsync(id);
            if(role==null)
            {
                return HttpNotFound();
            }

            var deleteVM = new RolesAdminDeleteViewModel
            {
                RoleId = role.Id,
                RoleName = role.Name
            };

            return View(deleteVM);
        }