Complete beginner to Rails here: 

In Rails:

I have a Model Post, which hasmany Tags. When creating a new Post, I want the user to be able to create up to 5 tags that are tied to the Post. 

I set up the form to create a new Post like this:

```
<%= form_for(@post) do |f| %>
   <div class="field">
      <%= f.label :name %><br/>
      <%= f.text_field :name %>
   </div>
   ... Some more of these
   <div class="field">   <!-- I want this to refer to the name attribute of a Tag model-->
      <%= f.label :tag_name %><br />
      <%= f.text_field :tag_name %>
   </div>
<% end %>

```

Obviously, this doesn't work since the Post class does not have a tag\_name attribute. What's the proper way to do this?

Assume that Tag is an aggregation table that has the following fields:

```
id: primary key
post_id: foreign key to Post's primary key
name: name of the tag

```