improve edge Dockerfile to accept branch arg

Author: DannyBen

edge/Dockerfile

@@ -3,8 +3,10 @@ FROM dannyben/alpine-ruby
 ENV PS1 "\n\n>> bashly \W \$ "
 RUN apk add --no-cache git
 
+ARG branch=master
+
 WORKDIR /bashly
-RUN git clone --depth 1 https://github.com/DannyBen/bashly.git .
+RUN git clone --branch $branch --depth 1 https://github.com/DannyBen/bashly.git .
 RUN gem build bashly.gemspec
 RUN gem install bashly*.gem
 

edge/op.conf

@@ -1,2 +1,2 @@
-build: docker build --no-cache -t dannyben/bashly:edge . && docker images |grep bashly
+build: docker build --build-arg=branch=$1 --no-cache -t dannyben/bashly:edge . && docker images |grep bashly
 push: docker push dannyben/bashly:edge