deis/deis — pull request #2241 by mave (2014-10-23 14:16:57+00:00)
Title: fix(builder): add config environment variables to Dockerfile when custom dockerfile is being used

I noticed that when pushing a repository with a custom Dockerfile to the builder, config environment variables that were set using `deis config:set key=value` were not being exported to the final docker image.
This PR appends the config variables to the Dockerfile, much like the GIT_SHA environment variable is appended currently.