Drone.io is a Continuous Delivery platform built on Docker, written in Go.
Drone is an CI platform built on Docker. Like many CI platforms, the idea is that your Drone instance listens to commits on your application's repository and builds your app according to some drone-specific files that you've created.
What makes Drone unique is that the build environment is a Docker container; you can choose from one of the provided build images, or use your own. This is a nice little application of Docker. Drone is also helped by a straightforward web-based UI and a growing development community. Because it allows for post-build actions, Drone can work nicely as a full CD solution.
Resources: Documentation | Q & A @ Stack Overflow