docs.rs failed to build free-0.0.1
Please check the build logs for more information.
See Builds for ideas on how to fix a failed build, or Metadata for how to configure docs.rs builds.
If you believe this is docs.rs' fault, open an issue.

$ curl -s https://static.rust-lang.org/rustup.sh | sudo sh

$ cargo build       ## build library and binary
$ cargo test        ## run tests in ./tests
$ cargo bench       ## run benchmarks in ./benches