A very basic example of a nested form.

Rails Nested Form Example

<form action="<%= posts_url %>" method="post">
  <label for="title">Title</label>
  <input type="text" name="post[title]" value="<%= @post.title %>">
  <br />
  <label for="link_1">Link 1</label>
  <input type="text" name="post[links_attributes][0][url]">>
  <br />
  <label for="link_2">Link 2</label>
  <input type="text" name="post[links_attributes][1][url]">
  <br />
  <label for="link_3">Link 3</label>
  <input type="text" name="post[links_attributes][2][url]">
  <br />
  <input type="submit" value="Update Post!">

</form>