This change allows using namespaced models with polymorphic_url,
in the way that you would use them without namespace.
Let's say that you have Blog::Post model in namespaced Engine. When you use
polymorphic_path with Blog::Post instances, like in form_for(@post),
it will look for blog_posts_path named url helper. As we are inside Blog::Engine,
it's annoying to always use the prefix. With this commit, blog_ prefix will be
removed and posts_path will be called.
1. use map instead of inject
2. use [].join("_") instead of '<<'. It is a little bit faster for ruby 1.9.2 and x2 faster for ruby 1.8.7. http://gist.github.com/548143
[#5450 state:resolved]
Signed-off-by: José Valim <jose.valim@gmail.com>