Add Docker file

Dockerfile

@@ -1,8 +1,8 @@
 FROM golang AS builder
-WORKDIR /go/src/proxy-to-gemini
-ADD . ./
-RUN CGO_ENABLED=0 go build -ldflags '-extldflags "-static"' -o /proxy-to-gemini
+WORKDIR /go/code
+ADD . /go/code
+RUN CGO_ENABLED=0 go build -o /proxy ./cmd/proxy-to-gemini
 
 FROM scratch
-COPY --from=builder /proxy-to-gemini /proxy-to-gemini
+COPY --from=builder /proxy /proxy-to-gemini
 ENTRYPOINT ["/proxy-to-gemini"]