ApplicationController common view

I created a user login system in ApplicationController. There is a def
called signin. It needs a view file, signin.rhtml

I have a couple of other controllers inheriting from
ApplicationController. Where can I place the view file so it is
viewable across all controllers? I tried the root view folder but that
didn't work.

Right now, I would have to copy and paste the signin.rhtml file into
all the controllers that I use the def signin.