cli: fix CLI usage, update README.md

.gitignore

···
 
 # Virtual environments
 .venv
+
+logbook.csv

README.md

···
 # foreflight-logbook-export
 
 Python library / script to export ForeFlight logbook
+
+## Usage
+
+To run it as a command line tool:
+
+```bash
+$ pip install git+https://tangled.sh/@itsze.ro/foreflight-logbook-export@main
+$ fflogex -u [username]
+```
+
+The program will ask you for your Foreflight password and the logbook will be
+saved to logbook.csv.
+
+## Library
+
+You can also alternatively use it as a library. See `cli.py` for how to use it.

fflogex/__init__.py

···
 from typing import Any, cast
 import requests
+from fflogex.cli import main
 
 
 class ForeflightLogbookExporter:
···
         """
 
         return self._session.get(link).text
+
+
+def main_cli():
+    main()

main.py fflogex/cli.py

···
     _ = parser.add_argument(
         "-p",
         "--password",
-        help="Specify password inline; You can also skip this and the program will ask you during the execution instead. Be careful your shell might record your password if you choose to use this option.",
+        help="Specify password inline; You can also skip this and the program will ask you during the execution instead. BE CAREFUL: Your shell might record your password if you choose to use this option.",
     )
     _ = parser.add_argument(
         "-o", "--output", help="Output file name (.csv)", default="logbook.csv"

pyproject.toml

···
 requires-python = ">=3.11"
 dependencies = ["requests>=2.32.3"]
 
+[project.scripts]
+fflogex = "fflogex:main_cli"
+
 [tool.pyright]
 venvPath = "."
 venv = ".venv"