docs(ref-resolver): add README.md

Author: P0lip

packages/ref-resolver/README.md

@@ -0,0 +1,26 @@
+# @stoplight/spectral-ref-resolver
+
+This package provides Spectral-compatible bindings for [@stoplight/json-ref-resolver](https://github.com/stoplightio/json-ref-resolver) and [@stoplight/json-ref-readers](https://github.com/stoplightio/json-ref-readers).
+
+You shouldn't need to install this package directly unless you want to create a custom JSON refs resolver
+
+## Installation
+
+```bash
+npm install --save @stoplight/spectral-ref-resolver
+
+# OR
+
+yarn add @stoplight/spectral-ref-resolver
+```
+
+## Usage
+
+An example usage of spectral-ref-resolver together with [proxy-agent](https://www.npmjs.com/package/proxy-agent).
+
+```js
+import { createHttpAndFileResolver, Resolver } from '@stoplight/spectral-ref-resolver';
+import ProxyAgent from import('proxy-agent');
+
+module.exports = createHttpAndFileResolver({ agent: new ProxyAgent(process.env.PROXY) });
+```