Ask HN: what's your policy for sharing on Github?

I'm a contract dev and sometimes I would like to contribute and make pull requests to projects on Github while I work. Supposing it's OK for the company to share that bit of work, how do you usually manage it user-wise? Do you use your own personal user? Does the company create one for you? I think there is no official way on Github of publishing something keeping my identity, but referencing the company where I was working, so that both can have credit. Am I wrong?