aliases: retire artist aliases after 2 years.

Automatically retire artist aliases after they're more than 2 years old.
Before the rule was that artist aliases were only retired if they didn't
have any new posts in the last 2 years.

app/logical/tag_relationship_retirement_service.rb

@@ -40,15 +40,15 @@ module TagRelationshipRetirementService
   end
 
   def inactive_relationships
-    (inactive_aliases + inactive_implications).uniq
+    (inactive_gentag_aliases + inactive_artist_aliases + inactive_implications).uniq
   end
 
   def inactive_implications
     TagImplication.active.empty.where.not(consequent_name: "banned_artist")
   end
 
-  def inactive_aliases
-    aliases = TagAlias.general.or(TagAlias.artist).active.where("tag_aliases.created_at < ?", THRESHOLD.ago)
+  def inactive_gentag_aliases
+    aliases = TagAlias.general.active.where("tag_aliases.created_at < ?", THRESHOLD.ago)
     aliases = aliases.select do |tag_alias|
       !tag_alias.consequent_tag.posts.exists?(["created_at > ?", THRESHOLD.ago])
     end
@@ -56,4 +56,8 @@ module TagRelationshipRetirementService
     aliases += TagAlias.active.empty
     aliases
   end
+
+  def inactive_artist_aliases
+    TagAlias.active.artist.where("tag_aliases.created_at < ?", THRESHOLD.ago)
+  end
 end