'Update the extra configuration of a table
@param tablename: the name of the table
@param attr: dict of attributes to update'

@classmethod
def configure(cls, tablename, **attr):

    config = current.model.config
    tn = (tablename._tablename if (type(tablename) is Table) else tablename)
    if (tn not in config):
        config[tn] = Storage()
    config[tn].update(attr)
    return
