title: Associations with simple_form an input field (not checkboxes, selects. or radios)
body: <p>I was hoping someone could please help me with a simple_form association that I'm trying to do.
  What I want to do is to create a simple_form for a music video that that has an association in the form of a has many through. My schema looks like this: </p>
  
  <pre><code>create_table "music_videos", force: true do |t|
  t.string  "song_title",  null: false
  t.string  "venue",       null: false
  t.string  "location",    null: false
  t.string  "description", null: false
  t.string  "url_id",      null: false
  t.integer "user_id",     null: false
  end
  
  create_table "music_videos_tags", id: false, force: true do |t|
    t.integer "music_video_id", null: false
    t.integer "tag_id",         null: false
  end
  
  add_index "music_videos_tags", ["music_video_id"], name:     
  index_music_videos_tags_on_music_video_id", using: :btree
  add_index "music_videos_tags", ["tag_id"], name: "index_music_videos_tags_on_tag_id",   
  using: :btree
  
  create_table "tags", force: true do |t|
    t.string "name", null: false
  end
  </code></pre>
  
  <p>Music Videos has many tags through music_video_taggings vice versa. But I'm confused on how to do accomplish the association with simple_form. I have a new.html.erb with a form like so:</p>
  
  <pre><code>&lt;h1&gt;Submit Your Video&lt;/h1&gt;
  
  &lt;%= simple_form_for @music_video url: music_videos_path, method: :post do |f| %&gt;
   &lt;%= f.input :song_title %&gt;
   &lt;%= f.input :venue %&gt;
   &lt;%= f.input :location, label: "City", collection: MusicVideo::CITY %&gt;
   &lt;%= f.input :description %&gt;
   &lt;%= f.input :url_id, label: "Paste url id ex. 82237472" %&gt;
   &lt;%= f.input :name, label: "Tag" %&gt;
   &lt;%= f.submit %&gt;
  </code></pre>
  
     
  
  <p>Now I know, I'm supposed to put an association for f.input :name, but I don't want checkboxes, selects, or radios. How can I do this? I thought about creating a form for both @music_videos, and @tags right at the top of the form, but I don't think that will work though.The errors that I keep receiving are that there is an undefined method name. Any ideas? I've been stuck on this for awhile. Some help would greatly be appreciated. Thanks.</p>