linked banned artist listing

app/models/artist.rb

@@ -179,8 +179,12 @@ class Artist < ActiveRecord::Base
           post.delete!
         end
         
-        tag_implication = TagImplication.create(:antecedent_name => name, :consequent_name => "banned_artist")
-        tag_implication.delay.process!
+        # potential race condition but unlikely
+        unless TagImplication.where(:antecedent_name => name, :consequent_name => "banned_artist").exists?
+          tag_implication = TagImplication.create(:antecedent_name => name, :consequent_name => "banned_artist")
+          tag_implication.delay.process!
+        end
+        
         update_column(:is_active, false)
         update_column(:is_banned, true)
       end

app/views/artists/_secondary_links.html.erb

@@ -1,6 +1,7 @@
 <% content_for(:secondary_links) do %>
   <menu>
     <li><%= link_to "Listing", artists_path %></li>
+    <li><%= link_to "Banned", banned_artists_path %></li>
     <li><%= link_to "Search", search_artists_path %></li>
     <li><%= link_to "New", new_artist_path %></li>
     <li><%= link_to "Recent changes", artist_versions_path %></li>