Cross-origin resource sharing (CORS) for Rocket applications
Rocket requires nightly Rust. You should probably install Rust with rustup, then override the code directory to use nightly instead of stable. See installation instructions.
In particular, rocket_cors is currently targetted for nightly-2017-07-13. Newer nightlies
might work, but it's not guaranteed.
To use the latest master branch, for example:
toml
rocket_cors = { git = "https://github.com/lawliet89/rocket_cors", branch = "master" }