update to change now.sh to vercel for one click deploy

readme.md

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 # Nexmo Number Insight API Dashboard
 
-[![Edit realtime-number-insight-dashboard-nextjs](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/nexmo-community/number-insight-dashboard-example/tree/master/) [![Remix on Glitch](https://cdn.glitch.com/2703baf2-b643-4da7-ab91-7ee2a2d00b5b%2Fremix-button.svg)](https://glitch.com/edit/#!/remix/nexmo-number-insight-dashboard) [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy) [![Deploy to now](https://deploy.now.sh/static/button.svg)](https://deploy.now.sh/?repo=https://github.com/nexmo-community/number-insight-dashboard-example&env=NEXMO_API_KEY&env=NEXMO_API_SECRET&env=MLAB_USERNAME&env=MLAB_PASSWORD&env=MLAB_URI&env=MLAB_COLLECTION_NAME&env=PUSHER_APP_ID&env=PUSHER_APP_KEY&env=PUSHER_APP_SECRET&env=PUSHER_APP_CLUSTER)
+[![Edit realtime-number-insight-dashboard-nextjs](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/nexmo-community/number-insight-dashboard-example/tree/master/) [![Remix on Glitch](https://cdn.glitch.com/2703baf2-b643-4da7-ab91-7ee2a2d00b5b%2Fremix-button.svg)](https://glitch.com/edit/#!/remix/nexmo-number-insight-dashboard) [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy) [![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/import/git?s=https%3A%2F%2Fgithub.com%2Fnexmo-community%2Fnumber-insight-dashboard-example&env=NEXMO_API_KEY&env=NEXMO_API_SECRET&env=MLAB_USERNAME&env=MLAB_PASSWORD&env=MLAB_URI&env=MLAB_COLLECTION_NAME&env=PUSHER_APP_ID&env=PUSHER_APP_KEY&env=PUSHER_APP_SECRET&env=PUSHER_APP_CLUSTER)
 
 This project demonstrates how to build a real time dashboard that uses data from the Nexmo Number Insight API to power charts and graphs.