```ruby
def render_new_petition_link(options = {})
  options[:data] = { :toggle => "modal" }
  if user_signed_in?
    link_to "發起連署", "#petition-start-up", options
  else
    link_to "登入以發起連署", "#sign-up", options
  end
end
```

```ruby
= render_new_petition_link :class => "xxxxx"
```