From http://api.rubyonrails.org/classes/ActionView/Helpers/UrlHelper.html#method-i-link_to

rails-link-to.md

Link to ViewHelper Rails

link_to(body, url, html_options = {})
  # url is a String; you can use URL helpers like
  # posts_path

link_to(body, url_options = {}, html_options = {})
  # url_options, except :method, is passed to url_for

link_to(options = {}, html_options = {}) do
  # name
end

link_to(url, html_options = {}) do
  # name
end