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

app/controllers/admin/users_controller.rb

@@ -127,7 +127,7 @@ class Admin::UsersController < Admin::AdminController
     user = User.where(id: params[:id]).first
     guardian.ensure_can_delete_user!(user)
     begin
-      if UserDestroyer.new(current_user).destroy(user, params.slice(:delete_posts, :block_email, :block_urls, :context))
+      if UserDestroyer.new(current_user).destroy(user, params.slice(:delete_posts, :block_email, :block_urls, :block_ip, :context))
         render json: {deleted: true}
       else
         render json: {deleted: false, user: AdminDetailedUserSerializer.new(user, root: false).as_json}

app/controllers/users_controller.rb

@@ -135,6 +135,7 @@ class UsersController < ApplicationController
     return fake_success_response if suspicious? params
 
     user = User.new_from_params(params)
+    user.ip_address = request.ip
     auth = authenticate_user(user, params)
     register_nickname(user)