add Dockerfile

Dockerfile

@@ -0,0 +1,13 @@
+FROM golang:alpine as builder
+
+ADD . /go/src/github.com/ginuerzh/gost/
+
+RUN go install github.com/ginuerzh/gost/cmd/gost
+
+FROM alpine:latest
+
+WORKDIR /bin/
+
+COPY --from=builder /go/bin/gost .
+
+ENTRYPOINT ["/bin/gost"]