public UserModel GetUserByUserName(string userName)
        {
            var client = GetClient();

            var userRecords = client.GetObjectsWithQuery(TABLE_NAME_USER, new { twitterUserName = userName });
            if (userRecords != null && userRecords.Length > 0) {
                var userRecord = userRecords[0];
                var userModel = new UserModel {
                    Id = ParseDataTypeConverter.ToString(userRecord[ParseTableConstants.UserTable_ColumnName_ObjectId]),
                    TwitterUserName = ParseDataTypeConverter.ToString(userRecord[ParseTableConstants.UserTable_ColumnName_TwitterUserName]),
                    Score = ParseDataTypeConverter.ToInt(userRecord[ParseTableConstants.UserTable_ColumnName_Score]),
                    DateLastScored = ParseDataTypeConverter.ToNullableDateTime(userRecord[ParseTableConstants.UserTable_ColumnName_UpdatedAt])
                };

                return userModel;
            }

            return null;
        }
 public static void SignUserOut()
 {
     User = null;
 }