djpeewee has no support for Field.db_column
Hi,

I would like to use PeeWee in an existing django project to run analytics queries. I tried it in the Django shell, but the queries failed because my model contained a field whose name did not match the actual database column name. This is because I am using `Field.db_column` for many fields. I'm using 2.8.1.

It would be great if the djpeewee `translate()` function would support models with custom `db_column` values.  Such behaviour could easily be enabled using an option passed to `translate()` to preserve backwards compatibility.

Thank you.
