Fix email default URL options missing

.env.example

@@ -1,3 +1,5 @@
+AKKOUNTS_DOMAIN=accounts.example.com
+
 SMTP_SERVER=smtp.example.com
 SMTP_PORT=587
 SMTP_LOGIN=accounts

config/environments/production.rb

@@ -62,6 +62,11 @@ Rails.application.configure do
   outgoing_email_address = ENV.fetch('SMTP_FROM_ADDRESS', 'accounts@localhost')
   outgoing_email_domain  = Mail::Address.new(outgoing_email_address).domain
 
+  config.action_mailer.default_url_options = {
+    host: ENV['AKKOUNTS_DOMAIN'],
+    protocol: "https",
+  }
+
   config.action_mailer.default_options = {
     from: outgoing_email_address,
     message_id: -> { "<#{Mail.random_tag}@#{outgoing_email_domain}>" },