Update Dockerfile

Dockerfile

@@ -1,5 +1,6 @@
 FROM golang:1.9-alpine as builder
 RUN apk add --update git
+RUN apk add ca-certificates
 
 WORKDIR /go/src/github.com/serverless/event-gateway
 COPY . .
@@ -13,9 +14,9 @@ RUN go get -u github.com/golang/dep/cmd/dep
 RUN dep ensure
 RUN go build -o event-gateway cmd/event-gateway/main.go
 
-FROM alpine:3.6
-RUN apk add --no-cache ca-certificates
-WORKDIR /app/
+FROM scratch
+WORKDIR /
 COPY --from=builder /go/src/github.com/serverless/event-gateway/event-gateway .
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 EXPOSE 4000 4001
-ENTRYPOINT ["./event-gateway"]
+ENTRYPOINT ["./event-gateway"]