[docker] add the sample Dockerfile and requirements.txt

for the baseline recsystem

Dockerfile

+FROM python:3.6-slim-buster
+WORKDIR /usr/src/app
+COPY requirements.txt ./
+# pip needs to be upgraded before some dependencies can be installed properly
+RUN pip install --upgrade pip
+RUN pip install --no-cache-dir -r requirements.txt
+COPY . .
+CMD [ "python", "baseline.py" ]

requirements.txt

+aiohttp==3.6.2
+click==7.1.2
+coloredlogs==14.0
+jsonrpcserver==4.1.3
+PyJWT==1.5.3
+websockets==8.1