fixing Dockerfile mistakes so that it will build

Author: relotnek

Dockerfile

@@ -2,9 +2,9 @@ FROM ruby:2.6.5
 RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
 RUN mkdir /myapp
 WORKDIR /myapp
-RUN bundle install --with=openshift
 ADD Gemfile /myapp/Gemfile
 ADD Gemfile.lock /myapp/Gemfile.lock
+RUN bundle install --with=openshift
 ADD . /myapp
 RUN chgrp -R 0 /myapp \
   && chmod -R g+rwX /myapp