Fix to make DockerImage run anywhere

Dockerfile

-FROM alpine:3.5
+FROM golang:alpine
 
-RUN apk add --no-cache ca-certificates
-
-ADD apache_exporter /
+RUN apk add --no-cache ca-certificates git
+RUN go get github.com/neezgee/apache_exporter
 
 EXPOSE 9117
-ENTRYPOINT ["/apache_exporter"]
+ENTRYPOINT ["/go/bin/apache_exporter"]
\ No newline at end of file

README.md

@@ -28,7 +28,6 @@ Tested on Apache 2.2 and Apache 2.4.
 Run the following commands from the project root directory.
 
 ```
-env GOOS=linux GOARCH=amd64 go build .
 docker build -t apache_exporter .
 ```