Moved backend to a separate directory

Dockerfile

@@ -33,13 +33,13 @@ ENV NODE_ENV production
 
 # cleanup
 USER root
-RUN rm -r ./src ./public/js-source ./bio-proxy-configuration-for-docker && \
+RUN rm -r ./backend/src ./backend/test ./public/js-source ./bio-proxy-configuration-for-docker && \
     npm cache clean --force
 USER appuser
 
 # healthcheck
 HEALTHCHECK --interval=10s --timeout=2s --start-period=15s \
-    CMD node ./out/healthcheck.js
+    CMD node ./backend/out/healthcheck.js
 
 # set command
 CMD npm run production