I upgraded a Rails 3.0 app to Rails 3.1 which involved putting this
/*
*= require_self
*= require_tree .
*/
in the application.css file. Howeve
soluction is add in config/assets.rb
#config/assets.rb
Rails.application.config.assets.precompile += %w(*.svg *.eot *.woff *.ttf *.gif *.png *.ico *.swf *.xap masonry.pkgd.min.js jquery.colorbox-min.js i18n/jquery.colorbox-pt-BR.js admin.css)
And Add in app/views/layouts/_adm_layout.html.erb
#app/views/layouts/_adm_layout.html.erb
<%= stylesheet_link_tag 'admin', media: 'all', 'data-turbolinks-track' => true %>