build: Add rules for CI

In CI, we want to perform the build of the project (which means
building, linting and checking go modules) and make sure that after
that, the git tree is still clean.

The CI will also run the tests using the testing postgres docker image
we added in an earlier commit.

Makefile

@@ -1,6 +1,7 @@
 GO111MODULE=on
 export GO111MODULE
 
+SHELL = /bin/bash
 VERSION ?= $(shell git describe --tags --always --dirty)
 DOCKER_CMD ?= "docker"
 DOCKER_REPO ?= "quay.io/flatcar"
@@ -14,6 +15,30 @@ all: backend tools frontend
 check:
 	go test -p 1 ./...
 
+container_id:
+	set -e; \
+	docker build \
+		--file Dockerfile.postgres-test \
+		--tag kinvolk/nebraska-postgres-test \
+		.; \
+	trap "rm -f container_id.tmp container_id" ERR; \
+	docker run \
+		--privileged \
+		--detach \
+		--publish 127.0.0.1:5432:5432 \
+		kinvolk/nebraska-postgres-test \
+		>container_id.tmp; \
+	docker exec \
+		$$(cat container_id.tmp) \
+		/wait_for_db_ready.sh; \
+	mv container_id.tmp container_id
+
+.PHONY: check-backend-with-container
+check-backend-with-container: container_id
+	set -e; \
+	trap "docker kill $$(cat container_id); docker rm $$(cat container_id); rm -f container_id" EXIT; \
+	go test -p 1 ./...
+
 .PHONY: frontend
 frontend:
 	cd frontend && npm install && npm run build
@@ -34,6 +59,16 @@ backend: tools/go-bindata tools/golangci-lint
 	go mod tidy
 	go build -o bin/nebraska ./cmd/nebraska
 
+.PHONY: test-clean-work-tree-backend
+test-clean-work-tree-backend:
+	@if ! git diff --quiet -- go.mod go.sum pkg cmd updaters tools/tools.go; then \
+	  echo; \
+	  echo 'Working tree of backend code is not clean'; \
+	  echo; \
+	  git status; \
+	  exit 1; \
+	fi
+
 .PHONY: tools
 tools:
 	go build -o bin/initdb ./cmd/initdb
@@ -63,3 +98,6 @@ container-postgres:
 
 .PHONY: container
 container: container-nebraska container-postgres
+
+.PHONY: backend-ci
+backend-ci: backend test-clean-work-tree-backend check-backend-with-container