Uninitialized constant "Controller Name"

It should be SchedulesController, not Users::ScheduleController. Controllers should only be namespaced when the route is namespaced with namespace. Controller names should also always be plural.

What you're creating is a nested resource, not a namespaced one.

Is the namespacing of the SchedulesController intentional? i.e. do you really mean to do this?

class Users::SchedulesController < ApplicationController

Or are you only doing that because schedules are a "sub-thing" from users?

The reason I ask this is because typically within Rails, nested resource controllers aren't namespaced. You would only namespace a controller if you wanted to modify the controllers in a special way under a namespace. A common example of this would be having some controllers under an admin namespace, inheriting from a BaseController within that namespace that would restrict only admins from acessing those controllers.

Option 1

If you didn't intentionally namespace this controller, then you want to remove the Users:: prefix from your controller, and move it back to app/controllers/schedules_controller.rb, the helpers back to app/helpers/schedules_helper.rb and the views back to app/views/schedules. Perhaps you ran a generator which also generated a Users::Schedule model, which should also need to be renamed to Schedule and moved back to app/models/schedule.rb.

Option 2

If you did intentionally namespace this controller, then you want to do this in your routes:

namespace :users do
  resources :schedules
end

Leave everything that's been generated as it should be.