I was looking for an application that could migrate issues from one of my Bitbucket repositories to one of my Github repositories.
I couldn't find anything already written but I found something close Git2BitIssues by tekstop. His application basically did the opposite of what I wanted. Moved things from Git to Bit not from Bit to Git. I built on it and achieved the desired result.
You can check out the code if you need something similar done.
This has been my first experience using collaborative coding on GitHub and I was amazed by how smoothly everything went.
The idea behind improving on someone else's code is that you first fork what he did. Basically you get a copy of his repository on your own account. You push your changes to this account and then you ask the author if he is ok with your changes via a pull request. It is all really easy and kind of fun.
Anyway now you can move your issues from one system to another with this application if you need to.
Cheers!