Add docker definitions

Dockerfile

@@ -0,0 +1,18 @@
+# syntax=docker/dockerfile:1
+FROM python:3
+
+RUN useradd -d /code pathogen
+RUN mkdir /code
+RUN chown pathogen:pathogen /code
+
+RUN mkdir /venv
+RUN chown pathogen:pathogen /venv
+
+USER pathogen
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+WORKDIR /code
+COPY requirements.txt /code/
+RUN python -m venv /venv
+RUN . /venv/bin/activate && pip install -r requirements.txt
+CMD . /venv/bin/activate && exec python /code/threshold