fix Dockerfile

.gitignore

@@ -1,3 +1,5 @@
 .idea/
+.glide/
 vendor/
 packer-builder-vsphere
+bin/

README.md

@@ -15,7 +15,7 @@ $ glide install
 
 4. Build the binaries
 ```
-$ sudo docker-compose up
+$ docker-compose run build
 ```
 
 5. The template for this builder is like following:

docker/Dockerfile

@@ -1,9 +1,5 @@
 FROM golang:1.7.1
 ARG GLIDE_VERSION=0.12.3
 
-RUN export DEBIAN_FRONTEND=noninteractive && \
-apt-get -qq update && \
-apt-get -y install zip
-
 RUN wget -nv https://github.com/Masterminds/glide/releases/download/v$GLIDE_VERSION/glide-v$GLIDE_VERSION-linux-amd64.tar.gz -O- | \
 tar xzf - -C /usr/local/bin/ --strip-components=1 linux-amd64/glide