FEATURE: Add welcome message for admins. (#8293)

app/models/concerns/roleable.rb

@@ -20,7 +20,7 @@ module Roleable
 
   def grant_moderation!
     set_permission('moderator', true)
-    enqueue_welcome_moderator_message
+    enqueue_staff_welcome_message(:moderator)
   end
 
   def revoke_moderation!
@@ -29,6 +29,7 @@ module Roleable
 
   def grant_admin!
     set_permission('admin', true)
+    enqueue_staff_welcome_message(:admin)
   end
 
   def revoke_admin!

app/models/user.rb

@@ -416,9 +416,17 @@ class User < ActiveRecord::Base
     Jobs.enqueue(:send_system_message, user_id: id, message_type: "welcome_tl1_user")
   end
 
-  def enqueue_welcome_moderator_message
-    return unless moderator
-    Jobs.enqueue(:send_system_message, user_id: id, message_type: 'welcome_moderator')
+  def enqueue_staff_welcome_message(role)
+    return unless staff?
+
+    Jobs.enqueue(
+      :send_system_message,
+      user_id: id,
+      message_type: 'welcome_staff',
+      message_options: {
+        role: role
+      }
+    )
   end
 
   def change_username(new_username, actor = nil)