Adds getting started docs for OS X

README.md

@@ -3,3 +3,31 @@
 Rust bindings to SpiderMonkey
 
 [Documentation](http://doc.servo.org/mozjs/)
+
+## Setting up your environment
+
+### Rust
+
+This project requires Rust nightly-2018-03-25 or greater.
+For installation of the Rust toolchain see [`https://rustup.rs/`](https://rustup.rs/).
+
+### Other dependencies
+
+#### macOS
+#### On macOS (Homebrew)
+
+```sh
+brew install automake pkg-config python2 cmake
+```
+
+## Building the project
+
+```sh
+cargo build
+```
+
+## Testing the project
+
+```sh
+cargo test
+```