Remove config/master.key from Docker Image

Dockerfile

@@ -88,6 +88,9 @@ EXPOSE 3000
 
 RUN chmod 755 /rails/bin/docker-entrypoint
 
+# Remove master key so that the Docker image does not have it
+RUN rm -f config/master.key
+
 ENV RAILS_ENV=production
 
 # Entrypoint prepares the database.

bin/docker-entrypoint

@@ -25,6 +25,11 @@ if [[ -z "${LD_PRELOAD+x}" ]] && [[ -f /usr/lib/*/libjemalloc.so.2 ]]; then
   export LD_PRELOAD="$(echo /usr/lib/*/libjemalloc.so.2)"
 fi
 
+# Create config/master.key from the env variable
+if [[ -n ${RAILS_MASTER_KEY} && ! -s config/master.key ]]; then
+  echo -n ${RAILS_MASTER_KEY} > config/master.key
+fi
+
 # If running the rails server then create or migrate existing database
 if [[ "${1}" == "./bin/rails" ]] && [[ "${2}" == "server" ]]; then
   ./bin/rails db:prepare