'Truncates the table passed as argument
If the database is in use, it will throw an OperationalError saying
database is locked
Usage:
Truncate table  gis_layer_config'

@staticmethod
def truncate_table(table_name):

    db = current.db
    s3db = current.s3db
    logger.info(('Truncating    table    %s' % table_name))
    table = s3db[table_name]
    table.truncate()
    db.commit()
