Forg/app/controllers/account_verifications_controller.rb

class AccountVerificationsController < ApplicationController
  skip_before_action :authenticate, only: [ :show ]

  def show
    user = User.find_by_token_for(:email_verification, params[:id])
    unless user
      flash[:alert] = t(".error")
      redirect_to :root and return
    end
    user.update(verified: true)
    UserMailer.with(user: user).email_verified.deliver_later
    flash[:notice] = t(".success")
    redirect_to login_path
  end
end