Netflix have been quite involved in the Jenkins project, including the Job DSL Plugin, which enables the automated creation of new Jenkins jobs, e.g. when a new Git branch is created, by defining the job structure with a simple Groovy-based DSL.

Taking this further, the upcoming release of Jenkins 2.0 is going to put a lot more emphasis on pipelines-as-code, where entire workflows can be defined in code, and version-controlled, as opposed to clicking everything together via the web UI.

See https://jenkins-ci.org/2.0/