element_path and collection_path define the URL format.
I didn't want .xml on the end of my URLs
AdhocResource << ActiveResource::Base has :
class << self
def element_path(id, options={})
"#{prefix(options}}#{collection_name}/#{id}#{query_string(options)}"
end
def collection_path(id, options={})
"#{prefix(options}}#{collection_name}#{query_string(options)}"
end
end