title: rails find_or_initialize on relationships
body: <p>when I create a new user, to avoid duplicates, I use the find_or_initialize method:</p>
  
  <pre><code>user = find_or_initialize_by_email(the_email)
  </code></pre>
  
  <p>If this user is created with a related company, how can I avoid the duplicates in companies?</p>
  
  <p>Can I do something like:</p>
  
  <pre><code>find_or_initialize_by_email_and_by_company_name(the_email, the_company_name)
  </code></pre>
  
  <p>Thanks!</p>