I am new to Ruby, using ruby 1.9.2P180 and Rails 3.1.0.rc2
I have \"screen.css\" in my_app_root/public/stylesheets/screen.css and in my application.html.erb
What am I doing wrong here?
Nothing, you are just using a default 3.1 install which uses the new sprockets-based asset pipeline.
put your stylesheets into /app/assets/stylesheets and use
<%= stylesheet_link_tag 'application.css' %>
in your views
the new pipeline takes all the stylesheets in that folder and automagically compiles them into a single file.
==
Alternatively, you can set turn the new pipline off in your application.rb with
config.assets.enabled = false