feat(roots/Dockerfile): add Delve

See https://github.com/derekparker/delve

Author: mboersma

README.md

@@ -13,6 +13,7 @@ creating [issues][] and submitting [pull requests][].
 * based on [Ubuntu 16.04][]
 * [az][]: Azure cloud command-line tool
 * [dep][]: Go dependency management tool
+* [delve][]: debugger for the Go programming language
 * [Docker][]: Docker binaries to be able to bind mount /var/run/docker.sock in the dev environment container
 * [gb][]: project-based build tool for Go
 * [ginkgo][]: BDD testing framework for Go
@@ -59,6 +60,7 @@ The latest deis/go-dev Docker image is available at:
 
 [az]: https://github.com/Azure/azure-cli#readme
 [Deis Workflow]: https://deis.com/
+[delve]: https://github.com/derekparker/delve
 [dep]: https://github.com/golang/dep
 [Docker Hub]: https://hub.docker.com
 [Docker]: http://www.docker.com

rootfs/Dockerfile

@@ -68,6 +68,7 @@ RUN \
     github.com/AlekSi/gocov-xml \
     github.com/axw/gocov/gocov \
     github.com/constabulary/gb/... \
+    github.com/derekparker/delve/cmd/dlv \
     github.com/dgrijalva/jwt-go/cmd/jwt \
     github.com/golang/protobuf/protoc-gen-go \
     github.com/haya14busa/goverage \