Fix Dockerfile code smells

Fixes #39

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Author: NikAcc

backend/Dockerfile

@@ -18,9 +18,9 @@ RUN apk update --no-cache \
 
 ENTRYPOINT ["sh", "/entrypoint.sh"]
 
-CMD python manage.py runserver 0.0.0.0:8000
+CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]
 
-FROM dev as prod
+FROM dev AS prod
 #ARG is required for the settings.py. Otherwise the build will fail, because required env variables have not been set
 ARG BUILD=1
 
@@ -32,4 +32,4 @@ USER baseuser
 EXPOSE 8000
 
 # Overwrites previous CMD from stage "dev"
-#CMD gunicorn securecheckplus.wsgi:application --bind 0.0.0.0:8000 --workers=2 --threads=2 --log-level INFO
+#CMD ["gunicorn", "securecheckplus.wsgi:application", "--bind", "0.0.0.0:8000", "--workers=2", "--threads=2", "--log-level", "INFO"]