updateData
    updateData(instanceData)
  
  Updates instance data given the serialized form of the data and
the url settings.
If url.updateData is a function, that function will be called.  If url.updateData is a
string, a request to that string will be made. If url is a string, a PUT request is made to
url+"/"+IDPROP.
Parameters
- instanceData 
{Object}:The serialized data of the instance.
 
Returns
 {Promise<Object>}: 
A promise that resolves to the updated instance data.