Merge pull request #501 from FormidableLabs/task/azure_ad_b2c_example

add azure ad b2c example config

Author: Austin McBee

docs/config-examples/azure-active-directory-b2c.md

@@ -0,0 +1,20 @@
+## Azure Active Directory B2C
+
+Detailed documentation [here](https://docs.microsoft.com/en-us/azure/active-directory-b2c/openid-connect).
+
+```js
+const config = {
+  issuer: 'https://<TENANT_NAME>.b2clogin.com/<TENANT_NAME>.onmicrosoft.com/<USER_FLOW_NAME>/v2.0',
+  clientId: '<APPLICATION_ID>',
+  redirectUrl: 'com.myapp://redirect/url',
+  scopes: ['openid', 'offline_access']
+};
+
+// Log in to get an authentication token
+const authState = await authorize(config);
+
+// Refresh token
+const refreshedState = await refresh(config, {
+  refreshToken: authState.refreshToken,
+});
+```