Fixed grunt-cli install in alpine -- See: https://stackoverflow.com/a/52196681

Author: hajowieland

Dockerfile

@@ -6,7 +6,7 @@ ENV REFRESHED_AT 2019-03-01
 
 RUN apk --update --no-cache add git openssh-client ruby ruby-ffi zlib-dev autoconf automake gcc make g++ optipng nasm
 RUN gem install compass --no-ri --no-rdoc
-RUN npm install -g grunt-cli
+RUN npm_config_unsafe_perm=true npm install -g grunt-cli
 
 WORKDIR /root