[docs] Add links to sandbox option in examples readme files

examples/create-react-app-with-typescript/README.md

@@ -16,6 +16,10 @@ npm install
 npm start
 ```
 
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/create-react-app-with-typescript)
+
 ## The idea behind the example
 
 This example demonstrates how you can use [Create React App](https://github.com/facebookincubator/create-react-app) with [TypeScript](https://github.com/Microsoft/TypeScript).

examples/create-react-app/README.md

@@ -16,6 +16,10 @@ npm install
 npm start
 ```
 
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/create-react-app)
+
 ## The idea behind the example
 
 This example demonstrates how you can use [Create React App](https://github.com/facebookincubator/create-react-app).

examples/gatsby-theme/README.md

@@ -16,6 +16,10 @@ npm install
 npm run develop
 ```
 
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/gatsby-theme)
+
 ## The idea behind the example
 
 The is an alternative example to [`/examples/gatsby`](https://github.com/mui-org/material-ui/tree/master/examples/gatsby) leveraging [gatsby-theme-material-ui](https://github.com/hupe1980/gatsby-theme-material-ui/tree/master/packages/gatsby-theme-material-ui).

examples/gatsby/README.md

@@ -16,6 +16,10 @@ npm install
 npm run develop
 ```
 
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/gatsby)
+
 ## The idea behind the example
 
 [Gatsby](https://github.com/gatsbyjs/gatsby) is a static site generator for React.

examples/nextjs-with-typescript/README.md

@@ -16,12 +16,9 @@ npm install
 npm run dev
 ```
 
-or
+or:
 
-```sh
-yarn
-yarn dev
-```
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/nextjs-with-typescript)
 
 ## The idea behind the example
 

examples/nextjs/README.md

@@ -16,6 +16,10 @@ npm install
 npm run dev
 ```
 
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/nextjs)
+
 ## The idea behind the example
 
 [Next.js](https://github.com/zeit/next.js) is a framework for server-rendered React apps.

examples/ssr/README.md

@@ -15,6 +15,9 @@ Install it and run:
 npm install
 npm run start
 ```
+or:
+
+[![Edit on CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/mui-org/material-ui/tree/master/examples/ssr)
 
 ## The idea behind the example