add Makefile for building dist files

Makefile

@@ -0,0 +1,30 @@
+TARGET_ARCH ?= amd64
+BUILD_DIR ?= build
+BIN_DIR := $(BUILD_DIR)/bbgo
+DIST_DIR ?= dist
+GIT_DESC  = $$(git describe --long --tags)
+
+all: bbgo
+
+$(BIN_DIR):
+	mkdir -p $@
+
+bin-dir: $(BIN_DIR)
+
+bbgo-linux: $(BIN_DIR)
+	GOOS=linux GOARCH=$(TARGET_ARCH) go build -o $(BIN_DIR)/$@ ./cmd/bbgo
+
+bbgo-darwin:
+	GOOS=darwin GOARCH=$(TARGET_ARCH) go build -o $(BIN_DIR)/$@ ./cmd/bbgo
+
+bbgo:
+	go build -o $(BIN_DIR)/$@ ./cmd/$@
+
+clean:
+	rm -rf $(BUILD_DIR)
+
+dist: bin-dir bbgo-linux bbgo-darwin
+	mkdir -p $(DIST_DIR)
+	tar -C $(BUILD_DIR) -cvzf $(DIST_DIR)/bbgo-$$(git describe --tags).tar.gz .
+
+.PHONY: dist