Call for contributors to the Rust Playground for upcoming features

(but not limited to) an increased number of crates available.

It looks like Rust Explorer uses a comment to declare dependencies. If/when you get to the point of designing how to specify that in the playground, I would be interested in collaborating on that. My hope is that by mid-year I'll have a Pre-RFC for a cargo-script design for shipping in rustup and think it'd be good to have these two systems use the same syntax.