gistfile1.rb

class UsersController < ApplicationController
  def new
    @user = User.new
  end

  def create
    @user = User.new params[:user]
    if @user.save
      format.html do
        email = EmailService.welcome_email user
        email.deliver
        redirect_to @user
      end
      format.json do
        render :json => @user,
          :status => :created,
          :location => @user
      end
    else
      format.html do
        render :new
      end
      format.json do
        render :json => @user.errors,
          :status => :unprocessable_entity
      end
    end
  end
end

class EmailService
  def self.welcome_email(user)
    email = UserMailer.welcome_email user
    email.deliver
  end
end