I did something similar with a project I lost interest in several years ago ( https://github.com/dbfit/dbfit - table-oriented database unit testing). Just gave over commit rights, and there's a whole bunch of people writing code for it and maintaining it now, still going strong. I occasionally look at the github repo, and always end up amazed how much it's moved on.
We use DbFit every day at our shop. It's really changed how we work (as DB developers). Was funny that I thought of this project right after reading this article, and how I should probably try and contribute, then I see this in the comments. :) Thanks!
People wanted to implement new things, support new databases, I felt overprotective of the design, but didn't have enough time to bring new contributors onboard. So I just kind of gave up, and that allowed me to think about it from a completely different perspective. If I just deleted it, then I wouldn't care too much about it any more. Giving away the keys was kind of the same, but without preventing others from contributing. And it worked out great.