Added example with Docker and Flask (#519)

* Added example with Docker and Flask

* set flask debug flag to False

* new line at the end of file

* format with black

---------

Co-authored-by: Ricardo Sanchez Alba <r2sanchezalba@gmail.com>

examples/docker-flask/Dockerfile

@@ -0,0 +1,28 @@
+# Use the official Python image as the base image
+FROM python:3.9-slim
+
+# Set the working directory
+WORKDIR /app
+
+# Copy the requirements file
+COPY requirements.txt .
+
+#Install the libcups library
+RUN apt-get update -y && apt-get install libcups2-dev -y
+# Install the Python packages
+RUN pip install --no-cache-dir -r requirements.txt
+RUN pip install python-escpos --pre
+
+# Install Git
+RUN apt-get update && \
+    apt-get install -y git && \
+    rm -rf /var/lib/apt/lists/*
+
+# Copy the Flask app
+COPY app.py .
+
+# Expose the port the Flask app will run on
+EXPOSE 8080
+
+# Run the Flask app
+CMD ["python", "app.py"]