chore: Update readme to include usage (#114)

* Update readme to include usage

Signed-off-by: Michael Beemer <[email protected]>

* Update README.md

Co-authored-by: Todd Baert <[email protected]>
Signed-off-by: Michael Beemer <[email protected]>

* remove iffe

Signed-off-by: Michael Beemer <[email protected]>

Co-authored-by: Todd Baert <[email protected]>

Author: beeme1mr

README.md

@@ -1,22 +1,32 @@
 # OpenFeature SDK for NodeJS
 
-![Experimental](https://img.shields.io/badge/experimental-breaking%20changes%20allowed-yellow)
-![Alpha](https://img.shields.io/badge/alpha-release-red)
+[![a](https://img.shields.io/badge/slack-%40cncf%2Fopenfeature-brightgreen?style=flat&logo=slack)](https://cloud-native.slack.com/archives/C0344AANLA1)
 [![codecov](https://codecov.io/gh/open-feature/node-sdk/branch/main/graph/badge.svg?token=3DC5XOEHMY)](https://codecov.io/gh/open-feature/node-sdk)
+[![npm version](https://badge.fury.io/js/@openfeature%2Fnodejs-sdk.svg)](https://badge.fury.io/js/@openfeature%2Fnodejs-sdk)
 [![Known Vulnerabilities](https://snyk.io/test/github/open-feature/node-sdk/badge.svg)](https://snyk.io/test/github/open-feature/node-sdk)
 
-## Alpha Checklist
+## Installation
 
-- [x] spec compliant
-- [x] contains test suite which verifies behavior consistent with spec
-- [x] contains test suite with reasonable coverage
-- [x] automated publishing
-- [ ] comprehensive readme
+```shell
+npm install @openfeature/nodejs-sdk
+```
 
-## Installation
+or
 
+```shell
+yarn add @openfeature/nodejs-sdk
 ```
-$ npm install @openfeature/nodejs-sdk   // installs the latest version
+
+## Usage
+
+```typescript
+import { OpenFeature } from '@openfeature/nodejs-sdk';
+
+OpenFeature.setProvider(new MyProvider());
+
+const client = OpenFeature.getClient();
+
+const value = await client.getBooleanValue('enabled-new-feature', false);
 ```
 
 ## Development
@@ -36,3 +46,17 @@ Run tests with `npm test`.
 Both ES modules and CommonJS modules are supported, so consumers can use both `require` and `import` functions to utilize this module. This is accomplished by building 2 variations of the output, under `dist/esm` and `dist/cjs`, respectively. To force resolution of the `dist/esm/**.js*` files as modules, a package json with only the context `{"type": "module"}` is included at a in a `postbuild` step. Type declarations are included at `/dist/types/`
 
 For testing purposes, you can add a comment containing "/publish" in any PR. This will publish an experimental SDK version with the git SHA appended to the version number.
+
+## Contributors
+
+Thanks so much to our contributors.
+
+<a href="https://github.com/open-feature/node-sdk/graphs/contributors">
+  <img src="https://contrib.rocks/image?repo=open-feature/node-sdk" />
+</a>
+
+Made with [contrib.rocks](https://contrib.rocks).
+
+## License
+
+Apache License 2.0