Implemented a function for developers to specify the `--depth` option of
the `git clone` command. refs #55
Merge pull request #62 from yosssi/add-git-depth-option

Implemented a function for developers to specify the `--depth` option of the `git clone` command
Add a Dockerfile for building Drone.io Docker containers.
Merge pull request #69 from whitlockjc/dockerfile

Add a Dockerfile for building Drone.io Docker containers.