@sandal should we make this more generic so it doesn't specifically rely on sendgrid or mailcatcher? I'm thinking something like this:

```ruby
if ENV['SMTP_ADDRESS']
  ActionMailer::Base.smtp_settings = {
    :address              => ENV["SMTP_ADDRESS"],
    :port                 => ENV["SMTP_PORT"] || 587,
    :domain               => ENV["SMTP_DOMAIN"],
    :user_name            => ENV["SMTP_USERNAME"],
    :password             => ENV["SMTP_PASSWORD"],
    :authentication       => ENV["SMTP_AUTH"],
    :enable_starttls_auto => ENV["SMTP_TLS"] == 'true'
  }
else
  warn "ActionMailer::Base.smtp_settings was not set!"
end
```

Then in our `.env.example` file we could do something like this:

```
### SendGrid SMTP ###

# SMTP_ADDRESS = smtp.sendgrid.net
# SMTP_DOMAIN = practicingruby.com
# SMTP_USERNAME = pr-user
# SMTP_PASSWORD = pr-pass
# SMTP_AUTH = plain
# SMTP_TLS = true

### MailCatcher SMTP ###

SMTP_ADDRESS = localhost
SMTP_PORT = 1025
```