artists/summary: remove list of top source domains.

Remove the list of most-used source domains from artist summaries. This
took up a lot of space and usually wasn't very useful. It was also slow.
We had to calculate this on every artist tag search so we could display
it in the Artist tab, even though usually the user didn't open the tab.

app/models/artist.rb

@@ -170,10 +170,6 @@ class Artist < ApplicationRecord
       end
     end
 
-    included do
-      memoize :domains
-    end
-
     def sorted_urls
       urls.sort {|a, b| a.priority <=> b.priority}
     end
@@ -200,31 +196,6 @@ class Artist < ApplicationRecord
     def clear_url_string_changed
       self.url_string_changed = false
     end
-
-    def map_domain(x)
-      case x
-      when "pximg.net"
-        "pixiv.net"
-
-      when "deviantart.net"
-        "deviantart.com"
-
-      else
-        x
-      end
-    end
-
-    def domains
-      Cache.get("artist-domains-#{id}", 1.day) do
-        domains = Post.raw_tag_match(name).pluck(:source).map do |x|
-          map_domain(Addressable::URI.parse(x).domain)
-        rescue Addressable::URI::InvalidURIError
-          nil
-        end
-
-        domains.compact.inject(Hash.new(0)) {|h, x| h[x] += 1; h}.sort {|a, b| b[1] <=> a[1]}
-      end
-    end
   end
 
   module NameMethods

app/views/artists/_summary.html.erb

@@ -24,14 +24,6 @@
       <% end %>
     </li>
   <% end %>
-  <% if artist.domains.any? %>
-    <li><strong>Domains</strong></li>
-    <ul class="list-bulleted">
-      <% artist.domains.each do |url, count| %>
-        <li><%= url %>: <%= count %></li>
-      <% end %>
-    </ul>
-  <% end %>
   <% if artist.urls.present? %>
     <li><strong>URLs</strong></li>
     <ul>