updated contribute.md to run examples (#110)

* updated contribute to run examples

* updated examples md

Author: Avi98

CONTRIBUTING.md

@@ -18,7 +18,8 @@ To start working on React Async, clone the repo and bootstrap the project:
 ```sh
 git clone https://github.com/async-library/react-async.git
 cd react-async
-yarn && yarn bootstrap
+yarn && yarn build:packages
+yarn bootstrap
 yarn build && yarn test
 ```
 
@@ -80,6 +81,12 @@ This runs all tests using various versions of `react` and `react-dom`, to check
 
 In the `examples` folder, you will find sample React applications that use React Async in various ways with various other libraries. Please add a new example when introducing a major new feature. Make sure to add it to `now.json` so it is automatically deployed when merged to `master`.
 
+To run sample examples on your local environments
+
+```sh
+yarn start:examples
+```
+
 ### Resolving issues
 
 Sometimes your dependencies might end up in a weird state, causing random issues, especially when working with the examples. In this case it often helps to run `yarn clean -y && yarn bootstrap`. This will delete `node_modules` from all packages/examples and do a clean install.