public async Task CreateOrUpdateCredentials(TwitterUserCredentials newCredentials)
        {
            var oldCredentials = Credentials.SingleOrDefault(o => o.TwitterId == newCredentials.TwitterId);

            if (oldCredentials == null)
            {
                Credentials.Add(newCredentials);
            }
            else
            {
                oldCredentials = newCredentials;
            }
        }
        public async Task <string> CreateCredentials(TwitterUserCredentials twitterUserCredentials)
        {
            var url                      = "http://lijonsolutionsdev.azurewebsites.net/api/twitter/accounts/credentials";
            var userCredentials          = JsonConvert.SerializeObject(twitterUserCredentials);
            HttpResponseMessage response = await httpClient.PostAsJsonAsync(url, userCredentials);

            if (response.IsSuccessStatusCode)
            {
                return(twitterUserCredentials.TwitterId);
            }
            else
            {
                return(null);
            }
        }