Create an on-demand backup of this repository.

Your task:
1. Create a timestamped archive of the current repository state
2. Include all files except those in .gitignore
3. Save the backup with a clear naming convention:
   - Format: `{repo-name}_backup_{YYYY-MM-DD}_{HH-MM}.tar.gz`
   - Or: `{repo-name}_backup_{YYYY-MM-DD}_{HH-MM}.zip`

4. Optionally, the user may specify:
   - Backup location (default: parent directory or ~/backups)
   - Compression format preference
   - Exclusion patterns beyond .gitignore

Confirm backup creation and report the file location and size.