http://coding.smashingmagazine.com/2013/01/03/starting-open-source-project/
Contributor Anyone who has had source code merged into the repository is considered a contributor. The contributor cannot access the repository directly but has submitted patches that have been accepted. Committer People who have direct access to the repository are committers. These people work on features and fix bugs regularly, and they submit code directly to the repository. Reviewer The highest level of contributor, reviewers are commanders who also have directional impact on the project. Reviewers fulfill their title by reviewing submissions from contributors and committers, approving or denying patches, promoting or demoting committers, and generally running the project.