def setup_backtrace_cleaner_path
      return unless Rails.backtrace_cleaner.instance_variable_get(:@root) == '/'
      Rails.backtrace_cleaner.instance_variable_set :@root, Rails.root.to_s
    end
def setup_backtrace_cleaner_path
      return unless Rails.backtrace_cleaner.instance_variable_get(:@root) == '/'
      Rails.backtrace_cleaner.instance_variable_set :@root, Rails.root.to_s
    end
Rails relies on backtrace cleaner to set the application root directory
 filter. The problem is that the backtrace cleaner is initialized before
 this gem. This ensures that the value of `root` used by the filter
 is correct.