Added a simple makefile

Makefile

@@ -0,0 +1,40 @@
+IMPORT := github.com/go-gitea/go-sdk
+
+PACKAGES ?= $(shell go list ./... | grep -v /vendor/)
+GENERATE ?= github.com/go-gitea/go-sdk/gitea
+
+.PHONY: all
+all: clean test build
+
+.PHONY: clean
+clean:
+	go clean -i ./...
+
+generate:
+	@which mockery > /dev/null; if [ $$? -ne 0 ]; then \
+		go get -u github.com/vektra/mockery/...; \
+	fi
+	go generate $(GENERATE)
+
+.PHONY: fmt
+fmt:
+	go fmt $(PACKAGES)
+
+.PHONY: vet
+vet:
+	go vet $(PACKAGES)
+
+.PHONY: lint
+lint:
+	@which golint > /dev/null; if [ $$? -ne 0 ]; then \
+		go get -u github.com/golang/lint/golint; \
+	fi
+	for PKG in $(PACKAGES); do golint -set_exit_status $$PKG || exit 1; done;
+
+.PHONY: test
+test:
+	for PKG in $(PACKAGES); do go test -cover -coverprofile $$GOPATH/src/$$PKG/coverage.out $$PKG || exit 1; done;
+
+.PHONY: build
+build:
+	go build ./gitea