feature request: day-specific goals

[patoncrispy]

Firstly, this is a really cool, simple tool and I'm really enjoying it so far - great work!

It would be really cool to be able to specify goals only on certain days of the week, like only on weekdays or weekends.

I'm relatively new to Rust, but would be happy to give this a go if it's something you'd like in this project. :)

[oppiliappan]

but would be happy to give this a go if it's something you'd like in this project.

Ideas and contributions are most welcome! However, this would require adding a different goal mechanism altogether, and break backwards compatibility with the existing serialization format.

I, personally, wouldn't be able to add this into dijo trivially with the amount of time I have at the moment.