title: rails storing id's from reference table
body: <p>When I submit a text field into <code>user_items</code> I want it to take the <code>ID</code> of that item from <code>master_list_items</code> and place it into the <code>master_list_items_id</code> column under <code>user_items</code></p>
  
  <p>I have added master_list_items.rb -- but I'm not sure of the relationship to add..</p>
  
  <p>Any suggestions?</p>
  
  <p><strong>master_list_items</strong></p>
  
  <pre><code>+----------------------+----+
  | name                 | id |
  +----------------------+----+       
  | Item A               | 1  |
  | Item B               | 2  |
  | Item C               | 3  |
  +----------------------+----+  
  </code></pre>
  
  <p><strong>user_items</strong></p>
  
  <pre><code>+---- +----------+----------------------+
  | uid | item     | master_list_item_id  |
  +-----+----------+----------------------+
  | 2   | Item A   | NULL                 |
  | 7   | Item C   | NULL                 |
  | 9   | Item C   | NULL                 |
  +-----+----------+----------------------+  
  </code></pre>