group :development do
  gem 'mailcatcher'
end

Rails.application.configure do
  # 他の設定

  # MailCatcherの設定
  config.action_mailer.delivery_method = :smtp
  config.action_mailer.smtp_settings = {
    address: '127.0.0.1',
    port: 1025
  }

  # メールの送信元アドレスの設定（必要に応じて変更）
  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
end

% mailcatcher
Starting MailCatcher
==> smtp://127.0.0.1:1025
==> http://127.0.0.1:1080

% rails generate mailer UserMailer

class UserMailer < ApplicationMailer
  default from: 'no-reply@example.com'

  def welcome_email(user)
    @user = user
    @url  = 'http://localhost:3000/login'
    mail(to: @user.email, subject: 'Welcome to My Awesome Site')
  end
end

class UsersController < ApplicationController
  def create
    @user = User.new(user_params)
    if @user.save
      UserMailer.welcome_email(@user).deliver_now
      redirect_to @user, notice: 'User was successfully created.'
    else
      render :new
    end
  end

  private

  def user_params
    params.require(:user).permit(:email, :password, :password_confirmation)
  end
end