Fix the assets regexp for non-js/css files

railties/lib/rails/application/configuration.rb

@@ -34,7 +34,7 @@ def initialize(*)
         @assets = ActiveSupport::OrderedOptions.new
         @assets.enabled    = false
         @assets.paths      = []
-        @assets.precompile = [ /\w+\.(?!js|css)$/, "application.js", "application.css" ]
+        @assets.precompile = [ /\w+\.(:?!js|css)$/, "application.js", "application.css" ]
         @assets.prefix     = "/assets"
 
         @assets.js_compressor  = nil