dotcloud/docker — pull request #4933 by vbatts (2014-03-31 21:21:14+00:00)
Title: ADD enhancement: allow adding from another image

Rather than adding an additional buildfile instruction, this enhancement
will use a mock-URI prefix of "image://", followed by a image name, and
a ":" suffix. (i.e. image://[registry[:port]][:tag]: )

Such that if you have a container that has a built artifact, you can
copy it over to a new/different image.

```
FROM vbatts/minimal-runtime

ADD image://vbatts/fat-buildtime:/build/server /server

CMD "/server"
```

Docker-DCO-1.1-Signed-off-by: Vincent Batts (github: vbatts)