Merge pull request #2603 from techAPJ/patch-1

FEATURE: allow staff to send multiple invites to same email

lib/guardian.rb

@@ -214,6 +214,10 @@ class Guardian
     user.admin?
   end
 
+  def can_send_multiple_invites?(user)
+    user.staff?
+  end
+
   def can_see_private_messages?(user_id)
     is_admin? || (authenticated? && @user.id == user_id)
   end