Remove unused mailer.sass

Author: sman591

app/assets/stylesheets/mailer.sass

@@ -12,4 +12,4 @@
 # application.js, application.css, and all non-JS/CSS in the app/assets
 # folder are already added.
 # Rails.application.config.assets.precompile += %w( admin.js admin.css )
-Rails.application.config.assets.precompile += %w[manage.css vendor/*.js vendor/*.css mailer.css]
+Rails.application.config.assets.precompile += %w[manage.css vendor/*.js vendor/*.css]