Add docker build tasks

Dockerfile

@@ -0,0 +1,6 @@
+FROM scratch
+ADD bin/ozuio_linux_amd64 /ozuio
+EXPOSE 8080
+VOLUME /data
+WORKDIR /
+CMD ["/ozuio", "--port", "8080", "--dir", "data"]

Makefile

@@ -73,3 +73,13 @@ package: dev-deps generate
 		-osarch=${OSARCH} \
 		-ldflags "-X main.Version=${VERSION}" \
 	&& gzip -9 pkg/${VERSION}/${BINNAME}_*
+
+bin/ozuio_linux_amd64: $(SOURCES)
+	CGO_ENABLED=0 GOOS=linux ARCH=amd64 \
+		go build -a -o bin/ozuio_linux_amd64 \
+		-ldflags "-X main.Version=${VERSION}"
+
+.PHONY: build-docker
+build-docker: bin/ozuio_linux_amd64
+	docker build -t "jimeh/ozu.io:latest" . \
+	&& docker tag "jimeh/ozu.io:latest" "jimeh/ozu.io:${VERSION}"