Cleanup of the node source when building

Author: jleeh

Dockerfile

@@ -1,14 +1,14 @@
 FROM golang:1.10-alpine
 
-WORKDIR /go/src/app
-ADD chainlink/ .
-
 RUN apk add --no-cache gcc musl-dev git openssl bzr \ 
     && go get -u github.com/golang/dep/cmd/dep
 
 RUN go get -u github.com/smartcontractkit/chainlink
 
+WORKDIR /go/src/github.com/smartcontractkit/chainlink
 RUN dep ensure
-RUN go build -o chainlink
+RUN go build -o /bin/chainlink
+
+RUN rm -rf /go/src
 
 CMD ["chainlink", "node"]