Be the same person to a remote git repository on multiple computers?

I develop on several machines, but I find that I have trouble when I push to a remote repository: It (currently Assembla but happened before on Github) thinks I'm a separate person. In Assembla I'm the "Anonym开发者_如何学Cous" user even though I changed my global config to match my name and email and even used the same SSH key. While this is only annoying right now, it might be a bigger problem in the future when me or someone else needs to know everything I've contributed to a project.

How can I make a remote repository think I'm the same person when I'm on multiple computers?

As a side note: Is there any way to associate all previous commits (I'm the only person on this current project) with me?

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You can update your previous commits using those instructions: http://book.git-scm.com/4_undoing_in_git_-_reset,_checkout_and_revert.html

But be careful with pushed commits, in worst case you can mess up the repo.