dockerfile: use multistage build, add dockerfile to ignore

.dockerignore

@@ -14,3 +14,4 @@ extras
 build
 transfersh-server/run.sh
 .elasticbeanstalk
+Dockerfile

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.7-alpine
+FROM golang:1.11-alpine as build
 LABEL maintainer="Remco Verhoef <remco@dutchcoders.io>"
 
 # Copy the local package files to the container's workspace.
@@ -7,6 +7,9 @@ ADD . /go/src/github.com/dutchcoders/transfer.sh
 # build & install server
 RUN go build -o /go/bin/transfersh github.com/dutchcoders/transfer.sh
 
-ENTRYPOINT ["/go/bin/transfersh", "--listener", ":8080", "--provider", "s3"]  
+FROM golang:1.11-alpine
+COPY --from=build /go/bin/transfersh /go/bin/transfersh
+
+ENTRYPOINT ["/go/bin/transfersh", "--listener", ":8080"]
 
 EXPOSE 8080 8080