Rails 4 - Bootstrap and CSS not showing on production server

Question

The bootstrap and CSS work perfectly in development for our rails 4.2 app.

Here is the login page in development:

After deploying (ubuntu 14.1), assets are precompiled with:

bundle exec rake assets:precompile RAILS_ENV=production

However the bootstrap and css are completely not showing any effect on production server. Here is the same login page in production:

The assets precompile seems not having any effect on production. What's could cause bootstrap and css not showing in production? Is there way to verify that the assets precompile is successful?

UPDATE: files under app/assets

Answer 1

  # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added)
  # config.assets.precompile += %w( search.js )

You might have to uncomment the above lines and add the js and css files you are compiling. Above line should be present in /config/environments/production.rb