• 使用 devise_async 发送邮件，按照这个教程做的。
  
• 可是却报如下错误，求解：
  

ArgumentError (wrong number of arguments (given 3, expected 1..2)):

app/controllers/users/registrations_controller.rb:13:in `create'
  Rendering /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout
  Rendering /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_source.html.erb
  Rendered /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_source.html.erb (4.9ms)
  Rendering /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb
  Rendered /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (3.2ms)
  Rendering /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb
  Rendered /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (1.6ms)
  Rendered /home/zhang/.rvm/gems/ruby-2.3.0/gems/actionpack-5.0.2/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout (27.7ms)

谢谢！