Refactor Dockerfile for improved clarity and usage instructions

- Simplified comments and updated usage instructions for local and HuggingFace Spaces deployment.
- Adjusted database handling instructions and default command for running the application.
- Removed unnecessary user creation and streamlined dependency installation process.

Dockerfile

@@ -1,80 +1,49 @@
-# ── Scripture Detector — HuggingFace Spaces compatible Dockerfile ─────────────
+# ── Scripture Detector ────────────────────────────────────────────────────────
 #
-# Usage on HuggingFace Spaces
-# ───────────────────────────
-# 1. Push this repo to a HF Space (Docker SDK).
-# 2. Add the following secrets in Space Settings → Variables and secrets:
-#      SD_SECRET_KEY   →  any long random string, e.g. `openssl rand -hex 32`
-#      GEMINI_API_KEY  →  your Google AI Studio key (optional; can be set in-app)
-#
-# Local usage (standard)
-# ──────────────────────
+# Build:
 #   docker build -t scripture-detector .
-#   docker run -p 7860:7860 scripture-detector
 #
-# Local usage with a persistent database (mount a host directory)
-# ───────────────────────────────────────────────────────────────
-#   docker run -p 7860:7860 \
-#     -v "$(pwd)/db_volume:/app/db" \
+# Run (ephemeral in-memory database — data resets on container restart):
+#   docker run -p 5001:5001 scripture-detector
+#
+# Run (persistent database — mount a host directory):
+#   docker run -p 5001:5001 \
+#     -v "$(pwd)/data_volume:/app/db" \
 #     -e SD_DB_DIR=/app/db \
-#     -e SCRIPTURE_DETECTOR_CACHE_DB=0 \
-#     scripture-detector
+#     -e GEMINI_API_KEY=your_key_here \
+#     scripture-detector python app.py
+#
+# The default CMD uses --cache-db (in-memory SQLite) which is ideal for
+# workshops and demos where persistence across restarts is not needed.
 # ─────────────────────────────────────────────────────────────────────────────
 
 FROM python:3.12-slim
 
-# ── System dependencies ───────────────────────────────────────────────────────
-RUN apt-get update && apt-get install -y --no-install-recommends \
-        git curl \
+# Install git (required by Hugging Face Spaces build system) and uv
+RUN apt-get update && apt-get install -y --no-install-recommends git \
     && rm -rf /var/lib/apt/lists/*
+RUN pip install --no-cache-dir uv
 
-# ── Non-root user (required by HuggingFace Spaces) ───────────────────────────
-RUN useradd -m -u 1000 user
 WORKDIR /app
 
-# ── Install uv (fast Python package manager) ─────────────────────────────────
-RUN pip install --no-cache-dir uv
 
-# ── Dependencies (cached layer — only re-runs when pyproject.toml changes) ───
-COPY --chown=user:user pyproject.toml uv.lock* ./
-RUN uv sync --no-dev --frozen || uv sync --no-dev
+# Copy dependency manifest first to leverage Docker layer caching.
+# Dependencies are only re-installed when pyproject.toml / uv.lock changes.
+COPY pyproject.toml uv.lock* ./
 
-# ── Application source ────────────────────────────────────────────────────────
-COPY --chown=user:user . .
-
-# ── Runtime environment ───────────────────────────────────────────────────────
-# Per-user in-memory database (each browser session gets its own isolated DB).
-ENV SCRIPTURE_DETECTOR_CACHE_DB=1
+# Sync dependencies (no dev extras)
+RUN uv sync --no-dev --frozen || uv sync --no-dev
 
-# Tell Flask/app.py to configure SameSite=None; Secure cookies so they work
-# inside HuggingFace's iframe embedding.
-ENV SD_BEHIND_PROXY=1
+# Copy application source
+COPY . .
 
-# Bind to all interfaces; HF Spaces expects port 7860.
+# Bind to all interfaces inside the container
 ENV SD_HOST=0.0.0.0
 ENV SD_PORT=7860
 
-# SD_SECRET_KEY should be set as a HF Space Secret (not hardcoded here).
-# If absent, a random key is generated at startup — sessions reset on redeploy.
-
-# Gunicorn needs to see the app module
-ENV PYTHONUNBUFFERED=1
-
-# ── Non-root user ─────────────────────────────────────────────────────────────
-USER user
-
+# Expose the Flask port
 EXPOSE 7860
 
-# ── Start gunicorn ────────────────────────────────────────────────────────────
-# Single worker: the per-session in-memory databases live in one process.
-# More than one worker would mean different workers have different session stores,
-# causing "I added a source but now it's gone" bugs.
-CMD ["uv", "run", "gunicorn", \
-     "--worker-class", "gthread", \
-     "--workers", "1", \
-     "--threads", "4", \
-     "--bind", "0.0.0.0:7860", \
-     "--timeout", "120", \
-     "--access-logfile", "-", \
-     "--error-logfile", "-", \
-     "app:app"]
+# Default: run with --cache-db (in-memory database, no volume needed).
+# To use a persistent database instead, override CMD and set SD_DB_DIR.
+CMD ["uv", "run", "python", "app.py", "--cache-db"]