Dockerfile in cfer-0.4.2 vs Dockerfile in cfer-0.5.0.pre.rc1

@@ -1,5 +1,7 @@
-FROM ruby:2.2
+FROM ruby:2.3
 COPY . /usr/src/app
 WORKDIR /usr/src/app
 RUN bundle install
+RUN rake install
+RUN cfer version