Improve readme

I used mux for a recent project and I thought I could provide some more information in this readme.
closes sanity-io#10 by adding a warning about the `playsinline` attribute. If I understand correctly, this attribute is not exposed and must be added programmatically?

README.md

@@ -1,8 +1,15 @@
 # Sanity Mux Video Player
 
-Play videos from MUX.com integrated with the Sanity plugin [`sanity-plugin-mux-input`](https://github.com/sanity-io/sanity-plugin-mux-input)
+> Play videos from MUX.com integrated with the Sanity plugin [`sanity-plugin-mux-input`](https://github.com/sanity-io/sanity-plugin-mux-input)
 
-# Using
+## Install
+```
+yarn add sanity-mux-player
+```
+
+## Usage
+
+### In a React application
 
 - First you need to have a `mux.videoAsset` asset document in your hand. These documents are referenced to in the type `mux.video` that you will use inside your own types.
 
@@ -22,7 +29,46 @@ Play videos from MUX.com integrated with the Sanity plugin [`sanity-plugin-mux-i
   width={number | percent}
 />
 ```
+_Autoplaying videos: Videos must be muted to start playing automatically. In Safari, the additional `playsinline` attribute is [required](https://webkit.org/blog/6784/new-video-policies-for-ios/) and must be added [programmatically](https://github.com/sanity-io/sanity-mux-player/issues/2)._
 
-# Codebox example
+#### Codebox example
 
 Run the test app on [Codesandbox](https://codesandbox.io/s/github/sanity-io/sanity-mux-player/tree/main/test-app)
+
+
+### In the Rich Text Editor
+You can embed the player in the Rich Text Editor. First add the `mux.video` type provided by `sanity-plugin-mux-input`, then import`sanity-mux-player` and use it as a preview component. For more information, you can follow the [video](https://www.youtube.com/watch?v=cy9fgZa8d90&) or [written](https://www.sanity.io/guides/how-to-embed-an-instagram-post-in-portable-text) tutorial from Sanity about embedding Instagram posts; the logic stays the same for embedding Mux videos.
+
+```js
+// schemas/documents/post.js
+import React from 'react'
+import SanityMuxPlayer from 'sanity-mux-player'
+
+export default {
+  type: "document",
+  title: "Blog post",
+  name: "post",
+  fields: [
+    {
+      type: "string",
+      name: "title"
+    },
+    {
+      title: "Body",
+      name: "body",
+      type: "array",
+      of: [
+      { type: "block" }, 
+      {
+        title: 'Video',
+        name: 'video',
+        type: 'mux.video',
+        preview: {
+          component: SanityMuxPlayer,
+          }
+      }]
+    }
+  ]
+}
+```
+