Add initial Docker and Alembic setup

Introduce a `docker-compose.yml` to define the services for backend and database with health checks. Add Alembic configurations for database migrations and an initial empty migration. Include backend-related Docker setup with an entrypoint script for database migration execution.

backend/Dockerfile

@@ -0,0 +1,37 @@
+# Use Python 3.12 as the base image
+FROM python:3.12-slim
+
+# Set working directory
+WORKDIR /app
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+ENV PYTHONPATH=/app
+
+# Install system dependencies
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends gcc postgresql-client \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Python dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code
+COPY . .
+
+# Set up entrypoint script
+# Note: entrypoint.sh is at the root of the backend directory, not in a scripts folder
+COPY entrypoint.sh /usr/local/bin/entrypoint.sh
+RUN chmod +x /usr/local/bin/entrypoint.sh
+
+# Expose port
+EXPOSE 8000
+
+# Set the entrypoint
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
+
+# Default command
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]