Added watch subcommand

[Stefanuk12]

This adds a simple watch command that automatically runs the process command whenever a file change / creation is found. It can be optimised by getting the process_options within the watch subcommand and passing it into the process command but I did not do this. Let me know if you would like that implemented.

Closes #98

[jeparlefrancais]

Instead of using a new command, could you add a flag to the process command instead? If you are unfamiliar with clap, add something to the Options struct in the src/cli/process.rs file:

    /// Watch files and directories for changes and automatically re-run
    #[arg(long, short)]
    watch: bool,

Then you can use this bool to branch the process function logic.

Feel free to reach out on discord too and ping me if you don't get a review within 2 days 🙂

[Stefanuk12]

Hey, sorry for the late reply. Been trying to get this to work and I'm getting the following error: (dyn Rule + 'static)` cannot be shared between threads safely the trait `Sync` is not implemented for `(dyn Rule + 'static)

I mostly copy pasted the code from the watch file.

        let mut watcher = notify::recommended_watcher(move |res: Result<notify::Event, notify::Error>| {
            match res {
                Ok(event) => {
                    if event.kind.is_create() || event.kind.is_modify() {
                        // this line is causing the problem
                        let Err(e) = process(*(resources.clone()), *(process_options.clone())) else { return };
                        log::error!("there was an process error while attempting to bundle: {:?}", e);
                    }
                }
                Err(err) => {
                    log::error!("there was an watcher error while attempting to bundle: {:?}", err);
                }
            }
        }).expect("failed to create watcher");

[jeparlefrancais]

I sent you an invite on discord, we could work on this together if you want some help 🙂