fixes #34: case sensitive blacklisted tags

app/models/user.rb

@@ -25,6 +25,7 @@ class User < ActiveRecord::Base
   validates_presence_of :email, :if => lambda {|rec| rec.new_record? && Danbooru.config.enable_email_verification?}
   validate :validate_ip_addr_is_not_banned, :on => :create
   before_validation :convert_blank_email_to_null
+  before_validation :normalize_blacklisted_tags
   before_save :encrypt_password
   after_save :update_cache
   before_create :promote_to_admin_if_first_user
@@ -247,6 +248,10 @@ class User < ActiveRecord::Base
     def blacklisted_tag_array
       Tag.scan_query(blacklisted_tags)
     end
+    
+    def normalize_blacklisted_tags
+      self.blacklisted_tags = blacklisted_tags.downcase if blacklisted_tags.present?
+    end
   end
   
   module ForumMethods