[examples] Set public key from environment variable (#291)

* use env variables in example

* add .env.local to gitignore

.gitignore

@@ -60,6 +60,7 @@ node_modules/
 # dotenv environment variables file
 .env
 .env.test
+.env.local
 
 # parcel-bundler cache (https://parceljs.org/)
 .parcel-cache

examples/community/.env.example

@@ -0,0 +1 @@
+PUBLIC_KEY=""

examples/community/src/app.tsx

@@ -2,6 +2,14 @@ import React from 'react'
 
 import { Community } from '@status-im/react'
 
-export const App = () => {
+const publicKey = process.env.PUBLIC_KEY
-  return <Community publicKey="<YOUR_COMMUNITY_KEY>" theme="light" />
+
+if (!publicKey) {
+  throw new Error(
+    'Add PUBLIC_KEY to your environment variables (see .env.example)'
+  )
+}
+
+export const App = () => {
+  return <Community publicKey={publicKey} theme="light" />
 }