fixes #1136 (and a few other cases)

app/logical/daily_maintenance.rb

@@ -5,6 +5,7 @@ class DailyMaintenance
     Upload.delete_all(['created_at < ?', 1.day.ago])
     ModAction.delete_all(['created_at < ?', 3.days.ago])
     Delayed::Job.delete_all(['created_at < ?'], 1.day.ago)
+    ApiCacheGenerator.new.generate_tag_cache
   end
   
   def prune_ad_hits

app/models/artist.rb

@@ -58,7 +58,7 @@ class Artist < ActiveRecord::Base
 
     module ClassMethods
       def normalize_name(name)
-        name.to_s.mb_chars.downcase.strip.gsub(/ /, '_')
+        name.to_s.mb_chars.downcase.strip.gsub(/ /, '_').to_s
       end
     end
 

app/models/user.rb

@@ -76,7 +76,7 @@ class User < ActiveRecord::Base
     module ClassMethods
       def name_to_id(name)
         Cache.get("uni:#{Cache.sanitize(name)}", 4.hours) do
-          select_value_sql("SELECT id FROM users WHERE lower(name) = ?", name.mb_chars.downcase.tr(" ", "_"))
+          select_value_sql("SELECT id FROM users WHERE lower(name) = ?", name.mb_chars.downcase.tr(" ", "_")).to_s
         end
       end
 

app/models/wiki_page.rb

@@ -156,6 +156,6 @@ class WikiPage < ActiveRecord::Base
       else
         match
       end
-    end.map {|x| x.mb_chars.downcase.tr(" ", "_")}
+    end.map {|x| x.mb_chars.downcase.tr(" ", "_").to_s}
   end
 end