Add Docker image publication recipe

Makefile

@@ -1,5 +1,7 @@
 DOKKU_HOST := dokku@dev.lookingfora.name
 SHELL := /bin/bash
+DOCKER_IMAGE_NAME ?= bornholm/oidc-test
+DOCKER_IMAGE_TAG ?= $(shell git describe)
 
 build:
 	CGO_ENABLED=0 go build -v -o ./bin/server ./cmd/server
@@ -37,4 +39,16 @@ dokku-deploy:
 	$(if $(shell git config remote.dokku-oidc-test.url),, git remote add dokku-oidc-test $(DOKKU_HOST):oidc-test)
 	git push -f dokku-oidc-test $(shell git rev-parse HEAD):refs/heads/master	
 
+docker-build:
+	docker build \
+		-f ./misc/dokku/Dockerfile \
+		-t $(DOCKER_IMAGE_NAME):latest \
+		.
+
+docker-release: docker-build
+	docker image tag $(DOCKER_IMAGE_NAME):latest $(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)
+	docker login
+	docker push $(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)
+	docker push $(DOCKER_IMAGE_NAME):latest
+
 .PHONY: lint watch build vendor tidy release

misc/dokku/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.13 AS build
+FROM golang:1.17 AS build
 
 ARG HTTP_PROXY=
 ARG HTTPS_PROXY=