add build target

Makefile

@@ -1,3 +1,8 @@
+B=$(shell git rev-parse --abbrev-ref HEAD)
+BRANCH=$(subst /,-,$(B))
+GITREV=$(shell git describe --abbrev=7 --always --tags)
+REV=$(GITREV)-$(BRANCH)-$(shell date +%Y%m%d-%H:%M:%S)
+
 docker:
 	docker build -t umputun/reproxy .
 
@@ -12,4 +17,10 @@ dist:
 race_test:
 	cd app && go test -race -mod=vendor -timeout=60s -count 1 ./...
 
-.PHONY: dist docker race_test
+build: info
+	- cd app && GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -ldflags "-X main.revision=$(REV)" -o ../dist/reproxy
+
+info:
+	- @echo "revision $(REV)"
+
+.PHONY: dist docker race_test bin info