verify_authenticity_token has not been defined

Check if your ApplicationController has a call to protect_from_forgery as follows:

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
end

Essentially calling protect_from_forgery adds verify_authenticity_token to the before_filter list, which you can skip in the other controllers.

Refer to protect_from_forgery documentation for more info.