no need for expose

Dockerfile

@@ -3,8 +3,6 @@ MAINTAINER Johannes Zellner <johannes@cloudron.io>
 
 ENV PATH /usr/local/node-4.2.1/bin:$PATH
 
-EXPOSE 4567
-
 RUN mkdir -p /app/code
 WORKDIR /app/code
 RUN git clone -b v0.8.x https://github.com/NodeBB/NodeBB.git .