Add note about migations and the CMD

bin/docker-entrypoint-production

@@ -3,8 +3,13 @@
 echo "entrypoint"
 echo "${*}"
 
+# NOTE: Enable this as you need to get migrations working in your deployed
+# (i.e. Production) environments. Match the condition check to what you have in
+# the Dockerfile CMD. I use puma in the production.Dockerfile as that's the
+# recommended option by the Puma team (https://github.com/puma/puma#rails), but
+# the default Rails Dockerfile uses `./bin/rails server`
+#
 # If running the rails server then create or migrate existing database
-# bundle exec puma -C config/puma.rb
 # if [ "${*}" == "./bin/rails server" ]; then
 #   ./bin/rails db:prepare
 # fi