.dockerignore support

[linux-china]

The .dockerignore file
If a file named .dockerignore exists in the source repository, then it is interpreted as a newline-separated list of exclusion patterns. Exclusion patterns match files or directories relative to the source repository that will be excluded from the context. Globbing is done using Go's filepath.Match rules.

The following example shows the use of the .dockerignore file to exclude the .git directory from the context. Its effect can be seen in the changed size of the uploaded context.

http://docs.docker.com/reference/builder/

[hsz]

@linux-china .dockerignore files are supported now with v0.8 release.