Added dockerfile for pulsar

Dockerfile

+FROM python:2.7-alpine
+
+ENV PYTHONUNBUFFERED 1
+ENV DEBIAN_FRONTEND noninteractive
+
+ADD ./requirements.txt /pulsar/ 
+
+RUN apk update \
+    # psycopg2 dependencies
+    && apk add --no-cache --virtual build-deps gcc python-dev musl-dev \
+    # CFFI dependencies
+    && apk --no-cache add libffi-dev py-cffi \
+    && apk --no-cache add make linux-headers \
+    \
+    # Install python requirements
+    && pip install --no-cache-dir -r /pulsar/requirements.txt \
+    \
+    # Remove build deps
+    && apk del build-deps \
+    && rm /var/cache/apk/*
+
+# Create pulsar user environment
+RUN adduser -D -g '' pulsar \
+    && mkdir -p /pulsar    
+    
+# Set working directory to /pulsar/
+WORKDIR /pulsar/
+
+# Add files to /pulsar/
+ADD . /pulsar
+
+# Change ownership to pulsar
+RUN python setup.py install \
+    && pulsar-config --auto_conda --host 0.0.0.0 \
+    && chown -R pulsar:pulsar /pulsar \
+    && chmod +x /usr/local/bin/pulsar
+    
+# Switch to new, lower-privilege user
+USER pulsar
+
+# gunicorn will listen on this port
+EXPOSE 8913
+
+CMD sh /usr/local/bin/pulsar
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