controller_relative_to

Returns a controller path for a new controller based on a previous controller path. Handles 4 scenarios:

• stay in the previous controller:

    controller_relative_to( nil, "groups/discussion" ) # => "groups/discussion"
  

• stay in the previous namespace:

    controller_relative_to( "posts", "groups/discussion" ) # => "groups/posts"
  

• forced move to the root namespace:

    controller_relative_to( "/posts", "groups/discussion" ) # => "posts"
  

• previous namespace is root:

    controller_relative_to( "posts", "anything_with_no_slashes" ) # =>"posts"