- Take a directory as first argument (the `guest` directory)
- Take a file `.json` as second argument:
- If the file already exists, it will add the informations to it.
- If the file already exists, it will add the informations to it. If some elements already exist in the original file, it will be replaced by new values.
- If it doesn't, the script must handle the creation of the file.
- Handle case when no one answered yes to the invitation: