RFC: Add multiple resources with the same name

[z38]

At the moment addResources() overwrites parts with the same name. Although it's possible to set Content-Disposition myself to get around this limitation, it would be nice if new parts can be added without setting headers manually.

I'm not sure about the implementation yet, maybe we could introduce an option like overwrite or append.

[Nyholm]

That is great feedback. There is no reason why we overwrite. Ive created an PR. Please try it and make sure it works properly.

See #32

[Nyholm]

Fixed by #32

[z38]

Thank you!