Update Dockerfile

1. Removes the MODULES ARG.
2. Replaces the final CMD with ENTRYPOINT. This allows the modules to be selected at run time of the docker, rather than compile time of the image.

docker/Dockerfile

@@ -31,5 +31,4 @@ COPY . .
 ARG REQUIREMENTS
 RUN pip install -r $REQUIREMENTS
 
-ARG MODULES
-CMD ["python","server.py","--enable-modules=$MODULES"]
+ENTRYPOINT ["python","server.py"]