Breaking change: Club members' endpoint

Breaking change: please be aware that from 20-02-2018 we will change the structure returned by the Cub members' endpoint in order to return also the join date to each club.

The new structure will be:

{
 "weekly": [
        {
            "username": "xxx",
            "joined": 1305310668,
        }
 ],
 "monthly": [
        {
            "username": "xxx",
            "joined": 1305310668,
        } ],
 "all_time": [
        {
            "username": "xxx",
            "joined": 1305310668,
        } ]
}