It's idealized of using IMapper for all naming. But if table or column is not in rule, we need new method to archive.
If struct or pointer of struct has TableName() string method, the return value will be the struct's table name.
engine.Table() can change the database table name for struct. The struct tag xorm:"'table_name'" can set column name for struct field. Use a pair of single quotes to prevent confusion for column's definition in struct tag. If not in confusion, ignore single quotes.