feat(Makefile): add target for building releases

* Add README and License files to archive
* Compress archives for smaller download size

https://github.com/kubernetes/helm/issues/999

Makefile

@@ -12,6 +12,7 @@ LDFLAGS   :=
 GOFLAGS   :=
 BINDIR    := $(CURDIR)/bin
 BINARIES  := helm tiller
+DIST_DIRS := find * -type d -exec
 
 .PHONY: all
 all: build
@@ -24,6 +25,17 @@ build:
 build-cross:
 	gox -output="_dist/{{.OS}}-{{.Arch}}/{{.Dir}}" -os="darwin linux windows" -arch="amd64 386" $(GOFLAGS) -tags '$(TAGS)' -ldflags '$(LDFLAGS)' k8s.io/helm/cmd/...
 
+# usage: make dist VERSION=v2.0.0-alpha.3
+.PHONY: dist
+dist: build-cross
+	( \
+		cd _dist && \
+		$(DIST_DIRS) cp ../LICENSE {} \; && \
+		$(DIST_DIRS) cp ../README.md {} \; && \
+		$(DIST_DIRS) tar -zcf helm-${VERSION}-{}.tar.gz {} \; && \
+		$(DIST_DIRS) zip -r helm-${VERSION}-{}.zip {} \; \
+	)
+
 .PHONY: check-docker
 check-docker:
 	@if [ -z $$(which docker) ]; then \