puzzle-scoreboard/app/policies/event_policy.rb

class EventPolicy < ApplicationPolicy
  def owner_or_admin
    if record == :event
      true
    else
      record.user.id == user.id || user.admin?
    end
  end

  def index?
    owner_or_admin
  end

  def new?
    owner_or_admin
  end

  def create?
    owner_or_admin
  end

  def show?
    owner_or_admin
  end
end