feat: reduced docker image size

Author: charlieysc

Dockerfile

@@ -1,9 +1,11 @@
 FROM golang:1.12.9
-
 LABEL maintainer="Ren xiaohuo <[email protected]>"
-
 WORKDIR /app
-
 COPY ./ .
+RUN GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o zli main/main.go
 
-RUN go build  -o $GOPATH/bin/zli main/main.go
+FROM alpine:latest  
+RUN apk --no-cache add ca-certificates bash
+WORKDIR /app
+COPY --from=0 /app/ .
+RUN mv zli /bin/zli

README.md

@@ -25,7 +25,7 @@ go get ./...
 Run the following command to generate the `zli` binary:
 
 ```go
-go build -o zli main.go
+go build -o zli main/main.go
 ```
 
 ### Install
@@ -147,9 +147,9 @@ zli contract call -a 305d5b3acaa2f4a56b5e149400466c58194e695f -t SubmitTransacti
 
 ### Running zli inside a Docker container
 
-An alternative to running `zli` as a native binary is to build (or download) the `go-zli` Docker image, and to run `zli` from inside the container. This option requires prior installation of Docker (refer to the [Docker installation page](https://docs.docker.com/install/)).
+An alternative to running `zli` as a native binary is to build (or download) the `zli` Docker image, and to run `zli` from inside the container. This option requires prior installation of Docker (refer to the [Docker installation page](https://docs.docker.com/install/)).
 
-1. Build the `go-zli` Docker image:
+1. Build the `zli` Docker image:
 
 ```bash
 sh build_docker_image.sh