How to customize Testopia to add additional fields in Product dashboard

Im trying to customize Testopia(Add-in to the Bugzilla) , to add a new tab in the product dashboard

The new tabmay be something like Requirements next to the Environment tab .

This bugzilla is Open source and i have all the source code available .

So Pl let me know how to make changes to the source code to achieve this feature.

Thanks in advance .