public ActionResult Edit(string id)
 {
     Tag retrievedTag = _tagRepository.RetrieveTagByNameAndUserId(id, Owner.Id);
     EditTagModel model = new EditTagModel
                              {
                                  TagDescription = retrievedTag.Description,
                                  TagText = retrievedTag.TagText,
                                  OrginalTagText = retrievedTag.TagText
                              };
     return View(model);
 }
        public ActionResult Edit(EditTagModel model)
        {
            Tag tag = _tagRepository.RetrieveTagByNameAndUserId(model.OrginalTagText, Owner.Id);
            Tag newTag = new Tag(model.TagText)
                             {
                                 Description = model.TagDescription ?? string.Empty,
                                 Id = tag.Id
                             };

            _tagRepository.Update(newTag, Owner.Id);
            model.UIMessage = "Tag successfully updated.";

            return View(model);
        }