message: Document that Tinkey can be installed with Homebrew.
diff: @@ -5,7 +5,14 @@ decrypt keysets with master keys residing in a remote key management service
  (KMS). Out of the box it supports AWS KMS and Google Cloud KMS. Adding support
  for other KMS is easy, and doesn't require modifying Tinkey.
  -## Build
  +## Install with Homebrew
  +
  +```sh
  +brew tap google/tink https://github.com/google/tink
  +brew install tinkey
  +```
  +
  +## Build from source
  - Install [Bazel](https://docs.bazel.build/versions/master/install.html)
  