buildhive from cloudbees.
Now I'd like to write about one incredible feature I discovered recently.
Here is it. BuildHive CI server tracs all pul requests to your repository. So what it do when it discover new pull request? It build your master with changes from pullrequest. Then CI server makes comment to your pull request in case build was succesfull or not (see screenshot above).
And last but not least. You CAN make pull requests to your own repo in case you need this feature and you owner of the repo.