Default follows for new users (#4871)

When a new user confirms their e-mail, bootstrap their home timeline
by automatically following a set of accounts. By default, all local
admin accounts (that are unlocked). Can be customized by new admin
setting (comma-separated usernames, local and unlocked only)

app/controllers/admin/settings_controller.rb

@@ -13,6 +13,7 @@ module Admin
       closed_registrations_message
       open_deletion
       timeline_preview
+      bootstrap_timeline_accounts
     ).freeze
 
     BOOLEAN_SETTINGS = %w(

app/controllers/auth/confirmations_controller.rb

@@ -2,4 +2,10 @@
 
 class Auth::ConfirmationsController < Devise::ConfirmationsController
   layout 'auth'
+
+  def show
+    super do |user|
+      BootstrapTimelineWorker.perform_async(user.account_id) if user.errors.empty?
+    end
+  end
 end