Remove guestbook.db from repository
- Deleted guestbook.db, a binary SQLite database file, from the repo.
- Added guestbook.db to .gitignore to prevent storing environment-specific binaries.
- This change enhances security and keeps the repository clean by not tracking generated files.
- Fixed port variable interpolation to use ${PORT:-8000} for a default value.
- Updated volume configuration to use a named volume (guestbook_data) mounted at /data.
- Improved YAML formatting for clarity.
- Hide comment field by default.
- Add JavaScript to reveal comment field when first name, last name, and location have at least 3 characters.
- Update form instructions to inform users about the comment field.
