Document working with Rails helpers — both built in and custom

[tubsandcans]

Many Rails apps utilize the app/helpers feature for code reusability when rendering. I cannot figure out how to integrate the methods defined under app/helpers/ into Phlex's rendering pipeline, which seems very much like the kind of thing that would be pointed out under a Rails migration guide.

The docs make it clear how to create custom "helpers" for tags, which is nice but I absolutely need the logic in my helpers to become accessible inside Phlex classes/views. Also, the docs like to use the word "helpers" both for Rails built-in helpers and Plex's helpers, without a single mention of the existence of user-defined helpers under app/helpers, which is mildly confusing.