add custom metadata in pcakage

[sai411]

Hi
I am trying to create rpm and deb packages , using fpm , and I successfully did that
But I want to add few custom metadata to the packages like
product_number or code_type or some other which my project specific
Is there any way to do that , I am unable to find any thing related to this in document.
there is no way to do that ? or if any way , kindly please help

Thanks in advance