Add Dockerfile

Dockerfile

@@ -0,0 +1,19 @@
+FROM golang:1.11-alpine as builder
+ENV GOPATH /go
+ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
+RUN apk add -U --no-cache git build-base ca-certificates gcc git bash && \
+    mkdir -p /go/src/github.com/semihalev /data && \
+    cd /go/src/github.com/semihalev/ && \
+    git clone https://github.com/semihalev/sdns.git && \
+    cd /go/src/github.com/semihalev/sdns/ && \
+    CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags '-extldflags "-static"' -v -o /go/bin/sdns .
+
+
+FROM scratch
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=builder /data /data
+COPY --from=builder /go/bin/sdns /app/
+
+EXPOSE 53/udp 53 853 8053 8080
+ENTRYPOINT ["/app/sdns"]
+CMD ["-config", "/data/sdns.toml"]