Configure ActionMailer with SMTP settings

[crawfoal]

Here is an example from an article by thoughtbot:

# .env
APPLICATION_HOST=localhost:3000
SMTP_ADDRESS=smtp.example.com
SMTP_DOMAIN=example.com
SMTP_PASSWORD=password
SMTP_USERNAME=username

# config/environments/production.rb
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: ENV.fetch("SMTP_ADDRESS"),
  authentication: :plain,
  domain: ENV.fetch("SMTP_DOMAIN"),
  enable_starttls_auto: true,
  password: ENV.fetch("SMTP_PASSWORD"),
  port: 587,
  user_name: ENV.fetch("SMTP_USERNAME")
 }
config.action_mailer.default_url_options = {
  host: ENV.fetch("APPLICATION_HOST"),
  port: ENV.fetch("PORT")
} # make sure these are set appropriately in dev and test too

Additionally, we need to change the following line in the devise initializer file:

config.mailer_sender = 'please-change-me-at-config-initializers-devise@example.com'

[crawfoal]

Do in same PR as issue #113 and #115

[crawfoal]

The Rails guides also have gmail specific instructions.