Rails ActionMailer User Mailer No Method - ruby-on-rails-5

Question

I'm not geting my user_mailer work. It says there's no method and I coudn't find out why:
From Rails:
NoMethodError in AtendimentosController#create
undefined method `welcome_email' for UserMailer:Module
From Rails C (manual test):
irb(main):027:0> ActionMailer::usermailer.send_welcome_email(from: "test#example.co", to: '...#gmail.com', subject: 'subjecto de teste', body: "Test")
Traceback (most recent call last):
2: from (irb):27
1: from (irb):27:in `rescue in irb_binding'
NoMethodError (undefined method `usermailer' for ActionMailer:Module)
class UserMailer is located at /mailers/user_mailer/user_mailer.rb :
class UserMailer < ApplicationMailer
def welcome_email(user)
mail(:to => #user.email, :subject => "Welcome!")
end
end
I'm calling at a controller:
def send_mail
UserMailer.welcome_email(self).deliver_later
end

Answer 1

You should move this class to /mailers/user_mailer.rb. When you put the file in a separate folder, it is required that the file begins with the Module ModuleName. So in your example, when you put this file in /mailers/user_mailer/user_mailer.rb it should look like this:
module UserMailer
class UserMailer < ApplicationMailer
def welcome_email(user)
mail(:to => #user.email, :subject => "Welcome!")
end
end
end
And then you call it: UserMailer::UserMailer.welcome_email(self).deliver