Email Basics

gistfile1.rb

Configure your email settings:
  In config/environments/development.rb:
    config.action_mailer.delivery_method = :smtp
    config.action_mailer.smtp_settings = {
      address:              'smtp.gmail.com',
      port:                 587,
      domain:               'localhost:3000',
      user_name:            ENV['GMAIL_EMAIL'],
      password:             ENV['GMAIL_PASSWORD'],
      authentication:       'plain',
      enable_starttls_auto: true  
    }
    config.action_mailer.default_url_options = { :host => 'localhost:3000' }

Verify an Email is sending out (Devise Forgot Password)

Create a new Mailer
  rails generate mailer UserMailer

Setup a welcome email message (method) 

  class UserMailer < ActionMailer::Base
    default from: "[email protected]"
    # Call email using: UserMailer.welcome(user).deliver
    def welcome(user)
      @user = user
      mail(to: @user.email, subject: "Welcome to DevPoint Labs!")
    end
  end

Create email views (html & text)
  app/views/user_mailer/welcome.html.erb
  app/views/user_mailer/welcome.text.erb
Verify Email is sending in Rails Console

Automatically send welcome email after a user is created
  in User.rb
  after_create :send_welcome_email

  private
  
  def send_welcome_email
    UserMailer.welcome(self).deliver
  end


______

Create a layout for your emails
  app/views/layouts/email.html.erb
Implement it in your mailers
  layout 'email'
Install letter_opener Gem
  gem "letter_opener"
  bundle install
  In development.rb
    config.action_mailer.delivery_method = :letter_opener
    config.action_mailer.default_url_options = { :host => 'localhost:3000' }