Updating Dockerfile with requested changes

Dockerfile

@@ -1,20 +1,21 @@
-# Builds the Gas scanner with 'docker build' command, and runs Gas on all Go
-# files in your current directory with 'docker run' command.
-#
 # Docker version must be 17.05 or higher to allow multistage build
-#
+# See build and run instructions in README.md
 
+# Builds Gas for utilization
 FROM golang:1.8.1-alpine as builder
 ENV workspace /go/src/github.com/GoASTScanner/gas
+ENV GOPATH /go
 COPY . $workspace
 WORKDIR $workspace
 
 RUN go vet $(go list ./... | grep -v /vendor/)
 RUN CGO_ENABLED=0 go build -o gas .
 
-FROM alpine:3.6
+########################################################
 
-LABEL MAINTAINER="David Graves <david.graves@hpe.com>"
+# Runs Gas on all Go files in the current directory when 
+# 'docker run' command in README is given
+FROM alpine:3.6
 
 COPY --from=builder /go/src/github.com/GoASTScanner/gas/gas /