I talked to one of my friend who uses jenkin-Docker framework in her company. So, Jenkin is an open source automation tool with plugins built for CI. Jenkin helps to automate entire process of software delivery life cycle. Jenkin picks up the code committed by devs, Compile->Build it->Validate it->Execute unit and integration tests and packages the code to be delivered, here Jenkin doesn’t deploy the code. We need some different tools for that, so there comes Docker
Docker is an Virtualization environment. It just takes few seconds to create server and deployment, its not exactly VM but create an image as vm and act as a container where you can deploy files and later test it, it can support more than one container so you can just schedule it and relax. Docker is gaining lot of popularity these days because it makes it possible to get far more apps running on the same old servers and it also makes it very easy to package and ship programs.