optimized docker build #72

Reduced size by more than half now

Dockerfile

 #
 # abc Dockerfile
-# docker build --build-arg ABC_BUILD=oss -t aviaryan/abc .
+# docker build --build-arg ABC_BUILD=oss -t abc .
 # private: docker build --build-arg ABC_BUILD=noss -t abc .
 # docker volume create --name abc
 # docker run -i --rm -v abc:/root abc login google
@@ -8,33 +8,37 @@
 #
 
 # Pull the base image
-FROM golang:1.8-alpine 
+FROM alpine:3.6
 MAINTAINER Avi Aryan <avi.aryan123@gmail.com>
 
 # Set GOPATH
 ENV GOPATH /go
 
+# certs
+RUN apk --update add --no-cache ca-certificates
+RUN update-ca-certificates
+
+# Get build variant
+ARG ABC_BUILD=oss
+ENV ABC_BUILD ${ABC_BUILD}
+
 # Make directories for the code
 RUN mkdir -p /go/src/github.com/appbaseio/abc
+RUN mkdir -p /abc
 
 # Add abc files
 ADD . /go/src/github.com/appbaseio/abc
 
-# Define working directory
-WORKDIR /go/src/github.com/appbaseio/abc
-
-# Get build variant
-ARG ABC_BUILD=oss
-ENV ABC_BUILD ${ABC_BUILD}
-
-# Run build
-RUN cd /go/src/github.com/appbaseio/abc && \
+# install
+RUN apk add --no-cache --virtual build-dependencies go libc-dev && \
+	cd /go/src/github.com/appbaseio/abc && \
 	go build -tags $ABC_BUILD ./cmd/abc/... && \
-	mv ./abc /go/bin/ && \
-	rm -rf /go/src && \
+	mv ./abc /abc/ && \
+	apk del build-dependencies && \
+	rm -rf /go && \
 	rm -rf /usr/local/go
 
-WORKDIR /go/bin
+WORKDIR /abc
 
 # Define default entrypoint
 # Entrypoint gets extra parameters from docker run