message: Update Readme
  Add Yarn installation
  Add dependency cross-fetch installation
diff: @@ -9,16 +9,24 @@ This is the JavaScript notifier for capturing errors in web browsers and reporti
  ## Installation
  -Using npm:
  +Using yarn:
  +```sh
  +yarn add airbrake-js
  +yarn add cross-fetch # add cross-fetch as peerDependency
  +```
  +
  +or Using npm:
  ```sh
  npm install airbrake-js
  +npm install cross-fetch # add cross-fetch as peerDependency
  ```
  or using Bower:
  ```sh
  bower install airbrake-js-client
  +bower install cross-fetch # add cross-fetch as peerDependency
  ```
  ## Setup
  