feat(build): reduce docker image size

Author: siddharthlatest

Dockerfile

@@ -1,13 +1,12 @@
-FROM golang:1.11-alpine as build
+FROM golang:1.11-alpine as builder
 
 # Install tools required for project
 # Run `docker build --no-cache .` to update dependencies
 RUN apk add --no-cache build-base git
 WORKDIR /arc
 
 # List project dependencies with go.mod and go.sum
-COPY go.mod .
-COPY go.sum .
+COPY go.mod go.sum ./
 
 # Install library dependencies
 RUN go mod download 
@@ -17,5 +16,12 @@ RUN go mod download
 COPY . .
 RUN make
 
+# Final stage: Create the running container
+FROM alpine:3.10.1 AS final
+
+# Import the compiled executable from the first stage.
+COPY --from=builder /arc /arc
+WORKDIR /arc
+
 EXPOSE 8000
 CMD ["build/arc", "--log", "stdout", "--plugins"]