Adding configurable e-mail blacklist

config/initializers/ostatus.rb

@@ -1,7 +1,9 @@
+# frozen_string_literal: true
+
 port  = ENV.fetch('PORT') { 3000 }
 host  = ENV.fetch('LOCAL_DOMAIN') { "localhost:#{port}" }
 https = ENV['LOCAL_HTTPS'] == 'true'
-  
+
 Rails.application.configure do
   config.x.local_domain = host
   config.x.hub_url      = ENV.fetch('HUB_URL') { 'https://pubsubhubbub.superfeedr.com' }