Appends data from an existing item that joins the old data and the new data together. If the value is an integer it will add up from 1 to 2 and if is a string then it will add "hello" and " world" together to make "hello world".
{"msg":"Cloud","action":"Append","Item":"foo","Data":"bar"}

If the item exists the server will send a success MSG:
{"MSG":"CloudDataAppended"}

If the item doesn't exists then the server will cancel the update and send:
{"MSG":"CloudDataNotFound"}

If the cloud space is too much for it to fit then the server will send and cancel adding the item:
{"MSG":"CloudSizeLimitReached"}

If the cloud account doesn't exists:
{"MSG":"CloudAccountNotRegistered"}