Use golang executables as wercker build artifact

wercker.yml

box: wercker/golang
build:
    steps:
        - wercker/setup-go-workspace
        - script:
            name: get dependencies
            code: go get -v ./...
        - script:
            name: build executable
            code: go build -a -v ./...
        - script: 
            name: move executable
            code: mv $GOPATH/bin/* $WERCKER_OUTPUT_DIR
deploy:
    steps:
        - script:
            name: list files
            code: ls -l ./