refactor(docker): clean up dockerfile and improve CMD syntax

- Remove redundant inline comments for better readability
- Replace backslash line continuation with bash -c for CMD instruction
- Remove commented out gunicorn configuration line
- Improve CMD formatting using proper bash string syntax

These changes make the dockerfile cleaner and more maintainable while
preserving the same functionality (migrate, collectstatic, runserver).

dockerfile

@@ -1,33 +1,24 @@
 FROM python:3.12-slim
 
-# Environment settings
 ENV PYTHONDONTWRITEBYTECODE=1
 ENV PYTHONUNBUFFERED=1
 
-# Set work directory
 WORKDIR /app
 
-# System dependencies
 RUN apt-get update && apt-get install -y \
     build-essential \
     curl wget \
     && rm -rf /var/lib/apt/lists/*
 
-# Copy dependency file
 COPY requirements.txt .
-
-# Install Python dependencies
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Copy project files
 COPY . .
 
-# Expose port
 EXPOSE 8000
 
-# Run migrations + collectstatic + gunicorn at runtime
+CMD bash -c "
-CMD \
+  python manage.py migrate &&
-  python manage.py migrate && \
+  python manage.py collectstatic --noinput &&
-  python manage.py collectstatic --noinput && \
+  python manage.py runserver 0.0.0.0:8000
-  python manage.py runserver 0.0.0.0:8000 && \
+"
-#   gunicorn config.wsgi:application --bind 0.0.0.0:8000 --workers 3