updates to latest

Dockerfile

-FROM rails:4.1
+FROM rails
 
 WORKDIR /usr/src/app
 
-ENV DISCOURSE_VERSION=1.4.7 \
+ENV DISCOURSE_VERSION=1.6.0.beta7 \
     RAILS_ENV=production \
     RUBY_GC_MALLOC_LIMIT=90000000 \
     DISCOURSE_DB_HOST=postgres \
@@ -18,4 +18,4 @@ RUN git clone --branch v${DISCOURSE_VERSION} https://github.com/discourse/discou
  && bundle install --deployment --without test --without development
 
 EXPOSE 3000
-CMD ["rails", "server"]
+CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]