The policy here is to add anyone who has contributed a fix as a developer on the project.
The official way to share your changes is to fork the project and create a pull request once your changes are published to your fork. Codeplex documents this process
here; there are blog posts with additional details like
this one here, though most tend to focus on github.
My personal preference for this project would be for you to create an issue documenting the problem you've found (you can do some searching to see if the issue already exists to save me some time) and indicate that you are working on a fix. This will hopefully keep others from duplicating your efforts. Then, you can reference the work item number in your commit message(s) prefixed with a '#' and CodePlex will link things up. Please commit often, separating code-clean-up related changes from actual fixes to make it easier to see what's going on.
If you're not a fan of a manual merge of changes you've already made I would try copying the changes you made directly overwriting the initial download from the fork and running the diff to see how things work out (hope that makes sense!).
The free
Visual Studio Community edition includes support for git. If you have Visual Studio 2012 you can try the
Visual Studio Tools for Git extension, but I don't have any experience with it. If you are comfortable with the command line and a bit of advanced setup, git has a
decent installer.
In the past CodePlex allowed larger uploads related to issues but I can't find any way to attach anything larger than 4mb anymore. If necessary, I'm willing to do the merge for you if you .ZIP things up and email a link or the whole thing to me at OpenDBDiff @ gmail.com. If you're familiar with a diff you're welcome to send just that to me - basically I'll do what I can to work with whatever you have.
Thanks for willingness to share your fixes; be sure to check out the other open source alternatives listed in the
Documentation in case any of them can save you some additional work!