YayC example suggestions

Co-Authored-By: J Connolly <[email protected]>

Author: tdumitrescu

lib/groups.js

@@ -27,11 +27,11 @@ class MixpanelGroups extends ProfileHelpers() {
 
         usage:
 
-            mixpanel.groups.set('company', 'Acme Inc.', 'Industry', 'Widgets');
+            mixpanel.groups.set('company', 'Acme Inc.', '$name', 'Acme Inc.');
 
             mixpanel.groups.set('company', 'Acme Inc.', {
                 'Industry': 'widgets',
-                'Plan': 'premium'
+                '$name': 'Acme Inc.',
             });
     */
     set(group_key, group_id, prop, to, modifiers, callback) {