Base GRPC Dockerfile

Dockerfile for creating the base gRPC development Docker instance. For now, this assumes that the development will be done on GCE instances, with source code on Git-on-Borg.

As of 2014/09/29, it includes

• git
• some useful tools like curl, emacs, strace, telnet etc
• downloads the gerrit-compute-tools and installs the script that allows access to gerrit when on git-on-borg
• a patched version of protoc, to allow protos with stream tags to work