Rails 4.2 not loading helpers

Question

I'm using Rails 4.2 on a project and the helper doesn't seem to be loading.

I've got a sessions_controller.rb:

class SessionsController < ApplicationController

    def new
        if signed_in?
            redirect_to admin_path
        else
            render layout: 'login'
        end
    end

    def create

        @controller_js = ''

        user = User.find_by(email: params[:session][:email].downcase)

        if user && user.authenticate(params[:session][:password])
            sign_in user
            # user.update_attribute(:sign_in_count, user.sign_in_count + 1)
            user.update_attribute(:last_login, DateTime.now)
      if user.admin?
        redirect_to admin_path
      else
        redirect_to user
      end
        else
            flash.now[:danger] = 'Invalid email/password combination'
            render layout: 'login'
        end

    end

    def destroy
        sign_out
        redirect_to root_url
    end

  end

And in my SessionsHelper.rb

    module SessionsHelper

    def sign_in(user)
        remember_token = User.new_remember_token
        cookies.permanent[:remember_token] = remember_token
        user.update_attribute(:remember_token, User.digest(remember_token))
        self.current_user = user
    end

end

But I get an error which is caused by the SessionsHelper not being loaded.

However when I add the method in the ApplicationController.rb it does work fine.

It seems to be Rails 4.2 issue?

But I'm not sure how to resolve in my case. Any ideas?