Added Azure documentation

README.md

@@ -17,6 +17,7 @@ Single sign-on (SSO) is a property of access control of multiple related, yet in
  * To test, do logout and try login with links below login page `[ Login with <name> ]`
 
 # Available providers
+ * Azure - https://docs.microsoft.com/azure/app-service/configure-authentication-provider-aad
  * Facebook - https://developers.facebook.com/docs/apps/
  * GitHub - https://developer.github.com/apps/building-oauth-apps/creating-an-oauth-app/
  * Google - https://developers.google.com/identity/protocols/OpenIDConnect

inc/provider.class.php

@@ -877,7 +877,7 @@ class PluginSinglesignonProvider extends CommonDBTM {
       }
 
       $email = false;
-      $email_fields = ['email', 'e-mail', 'email-address'];
+      $email_fields = ['email', 'e-mail', 'email-address', 'mail'];
 
       foreach ($email_fields as $field) {
          if (isset($resource_array[$field]) && is_string($resource_array[$field])) {