public HttpResponseMessage List()
 {
     var engine = new WordEngine();
     var wordList = engine.GetWordList();
     return Request.CreateResponse(HttpStatusCode.OK, wordList);
 }
 public HttpResponseMessage Expire(UpdateWordRequest request)
 {
     var engine = new WordEngine();
     engine.Expire(request);
     return Request.CreateResponse(HttpStatusCode.Created);
 }