add_flash_types

Creates new flash types. You can pass as many types as you want to create flash types other than the default `alert` and `notice` in your controllers and views. For instance:

# in application_controller.rb
class ApplicationController < ActionController::Base
  add_flash_types :warning
end

# in your controller
redirect_to user_path(@user), warning: "Incomplete profile"

# in your view
<%= warning %>

This method will automatically define a new method for each of the given names, and it will be available in your views.