Add screening by IP address. When deleting a user as a spammer, block all signups from the same IP address.

app/serializers/screened_ip_address_serializer.rb

@@ -0,0 +1,12 @@
+class ScreenedIpAddressSerializer < ApplicationSerializer
+  attributes :ip_address,
+             :action,
+             :match_count,
+             :last_match_at,
+             :created_at
+
+  def action
+    ScreenedIpAddress.actions.key(object.action_type).to_s
+  end
+
+end