Rotate filename format

[jujuchang]

datePattern can and will only prepend at the beginning of the filename. Something like 'dev-2017-05-17-apps.log' can't be done. Please allow users to determine the filename format on where to place the date.

[sandman45]

Yea this would be awesome. We want to do this idt-2017-01-10.log but i cannot as it is currently

[jujuchang]

I have overwritten some of the winston functions to achieve this.

[mattberther]

Some long-overdue refactoring of the transport has occured. A PR is available at #107. Also, a pre-release version has been published to npm.

A key feature of the refactoring is that you can now put %DATE% anywhere in your filename. Also, momentjs formats are used so you have much more control over the final filename. Review the PR to see the updated options.

Please npm install [email protected] and reopen this issue if the problem remains.