anchor.diff:    }
   
     _performChangeUser(String _json) {
  -    _user = _json2user(_json, onError: (msg) => _me.displayWhenEmpty = msg);
  +    var user = _json2user(_json, onError: (msg) => _me.displayWhenEmpty = msg);
  +    setState(() => _user = user);
     }
   
     _performChangeFriends(List<String> _allJson) {
  -    _allJson
  +    var all = _allJson
           .map(_json2user)
  -        .where((o) => null != o)
  -        .forEach(_friendUsers.add);
  +        .where((o) => null != o);
  +    setState(() => all.forEach(_friendUsers.add));
     }
   
     bool _addFriend(String _json) {
       CodeWarsUser friend = _json2user(_json);
       if (null != friend) {
         _friendUsers.add(friend);
  -      // TODO Add to database
  +      SharedPreferences.getInstance().then((sp) =>
  +          sp.setStringSet(DatabaseKeys.FRIENDS, _friendUsers.map((obj) => obj.username).toSet()));
         return true;
       }
       return false;
  
positive.code: 
    _changeTheBossOfThisGym() {
      SharedPreferences.getInstance().then((sp) {
        setState(() {
          _performChangeUser(sp.getString(DatabaseKeys.USER) ??
              CodeWarsAPI.getErrorWithReason("not set"));
          _performChangeFriends(sp.getStringSet(DatabaseKeys.FRIENDS) ?? const[]);
        });
      });
    }
  
  
negative.code:         onPressed: () {
            setState(() => _refreshingFriend = user);
            get(CodeWarsAPI.getUser(user.username))
              ..then((val) {
                int index = _friendUsers.indexOf(user);
                CodeWarsUser u = _json2user(val.body);
                setState(() {
                  _friendUsers.removeAt(index);
                  _friendUsers.insert(index, u);
                  _refreshingFriend = null;
                });
                SharedPreferences.getInstance().then((sp) =>
                    sp.setString(DatabaseKeys.friendData(user.username), val.body));
              })
              ..timeout(new Duration(seconds: 10))
              ..catchError(() {
                _pop();
                setState(() => _refreshingFriend = null);
              });
          },),
        title: new ListTile(
          title: new Text(
  