FEATURE: Support multiple groups in the `custom_nav_group` setting

FEATURE: Support multiple groups in the custom_nav_group setting

diff --git a/config/settings.yml b/config/settings.yml
index 0187670..e76adf9 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -1,5 +1,8 @@
 plugins:
   prometheus_alert_receiver_enabled: true
   prometheus_alert_receiver_opsgenie_api_key: ''
-  prometheus_alert_receiver_custom_nav_group: ''
+  prometheus_alert_receiver_custom_nav_group: 
+    default: ''
+    type: list
+    list_type: compact
   prometheus_alert_receiver_enable_assign: true
diff --git a/plugin.rb b/plugin.rb
index 79b6810..4a418e6 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -82,7 +82,7 @@ after_initialize do
   add_to_class(:user, :include_alert_counts?) do
     @include_alert_counts ||= begin
       SiteSetting.prometheus_alert_receiver_custom_nav_group.blank? ||
-      groups.exists?(name: SiteSetting.prometheus_alert_receiver_custom_nav_group)
+      groups.exists?(name: SiteSetting.prometheus_alert_receiver_custom_nav_group.split("|"))
     end
   end

GitHub sha: ec9d997d