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

app/controllers/admin/screened_ip_addresses_controller.rb

@@ -0,0 +1,8 @@
+class Admin::ScreenedIpAddressesController < Admin::AdminController
+
+  def index
+    screened_emails = ScreenedIpAddress.limit(200).order('last_match_at desc').to_a
+    render_serialized(screened_emails, ScreenedIpAddressSerializer)
+  end
+
+end