public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            Hashtag hashtag = Hashtags.FirstOrDefault(h => h.Tekst.Equals(reader.Value.ToString()));

            if (hashtag == null)
            {
                hashtag = new Hashtag()
                {
                    ID = Hashtags.Count, Tekst = reader.Value.ToString()
                };
                Hashtags.Add(hashtag);
            }
            return(hashtag);
        }
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            Hashtag hashtag = (Hashtag)value;

            writer.WriteValue(hashtag.Tekst);
        }