Add some sample usage notes

Author: jonchardy

README.md

@@ -5,6 +5,11 @@
 This project provides a basic example of using GoJS in a React app.
 Check out the [Intro page on using GoJS with React](https://gojs.net/alpha/intro/react.html) for more information.
 
+When running the sample, try moving around nodes, editing text, relinking, undoing (Ctrl-Z), etc. within the diagram
+and you'll notice the changes are reflected in the inspector area. You'll also notice that changes
+made in the inspector are reflected in the diagram. If you use the React dev tools,
+you can inspect the React state and see it updated as changes happen.
+
 This project was bootstrapped with [Create React App](https://github.com/facebook/create-react-app).
 It also uses immer to simplify state update operations.
 

src/App.css

@@ -3,4 +3,9 @@ label {
   color: #212121; /* Grey 900 */
   display: block;
   padding: 2px;
+}
+
+p {
+  font: 300 1rem Roboto, helvetica, sans-serif;
+  color: #212121; /* Grey 900 */
 }

src/App.tsx

@@ -265,6 +265,15 @@ class App extends React.Component<{}, AppState> {
 
     return (
       <div>
+        <p>
+          Try moving around nodes, editing text, relinking, undoing (Ctrl-Z), etc. within the diagram
+          and you'll notice the changes are reflected in the inspector area. You'll also notice that changes
+          made in the inspector are reflected in the diagram. If you use the React dev tools,
+          you can inspect the React state and see it updated as changes happen.
+        </p>
+        <p>
+          Check out the <a href='https://gojs.net/alpha/intro/react.html' target='_blank' rel='noopener noreferrer'>Intro page on using GoJS with React</a> for more information.
+        </p>
         <Diagram
           nodeDataArray={this.state.nodeDataArray}
           linkDataArray={this.state.linkDataArray}