Prevent AssetTagHelper from crashing if RAILS_ROOT is not defined. Fixes...

Prevent AssetTagHelper from crashing if RAILS_ROOT is not defined. Fixes compatibility with Passenger. [#84 state:resolved]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

railties/lib/initializer.rb

@@ -28,7 +28,11 @@ def logger
     end
   
     def root
-      RAILS_ROOT
+      if defined?(RAILS_ROOT)
+        RAILS_ROOT
+      else
+        nil
+      end
     end
   
     def env
@@ -40,7 +44,7 @@ def cache
     end
 
     def public_path
-      @@public_path ||= File.join(self.root, "public")
+      @@public_path ||= self.root ? File.join(self.root, "public") : "public"
     end
 
     def public_path=(path)