Add deduplication

[serhii73]

No description provided.

[serhii73]

    with lock:
        message = request.json.get('message')
        id = request.json.get('id')
        if id and not id in tr_id:
            messages.append(message)
            tr_id.append(id)
        else:
            messages.append(message)

That's working, it looks like the id could be None.

[nestoroprysk]

Good job!