Breaking change: Player club's endpoint

Breaking change: please be aware that from Wed, 14-02-2018 we will change the structure returned by the Player's clubs endpoint in order to return also the join date to each club.

The new structure will be:

{
    "clubs": [
        {
            "url": "https://api.chess.com/pub/club/test",
            "joined": 1305310668,
            "last_activity": 1305310668
        },
        {
            "url": "https://api.chess.com/pub/club/test2",
            "joined": 1325883967,
            "last_activity": 1305310668
        }
   ]   
}