Fix to use API Key for authentication

Signed-off-by: Kotaro Inoue <[email protected]>

Author: musaprg

config/environments/production.rb

@@ -67,8 +67,8 @@
     address: 'smtp.sendgrid.net',
     port: 587,
     domain: 'heroku.com',
-    user_name: ENV['SENDGRID_USERNAME'],
-    password: ENV['SENDGRID_PASSWORD'],
+    user_name: 'apikey',
+    password: ENV['SENDGRID_API_KEY'],
     authentication: 'plain',
     enable_starttls_auto: true
   }