Require mailer config on staging and production
This will raise an error when Rails tries to boot without the ENV
variables. On Heroku staging and production, dynos will crash
until the config variables are added (and the dynos restarted, which
happens automatically when config variables are added).
Enable SMTP/TLS in SMTP settings
Be more secure by default.
Recommended by SendGrid http://sendgrid.com/docs/Integrate/Frameworks/rubyonrails.html
Merge pull request #7 from craftsmen/smtp

SMTP settings updates