title: Should I return id of associated entity or whole entity
body: <p>OK, lets assume we have two entities: <strong>Profile</strong>, consisting of <code>id</code>, name and ~10 irrelevant fields, and <strong>Post</strong>, consisting of <code>text</code>, <code>title</code>, and it's <code>author</code> (Profile). Also, there is resource <em>/feed</em> that returns feed containing posts from different profiles. </p>
  
  <p>So I have two options:</p>
  
  <ol>
  <li>Send full <strong>Profile</strong> entity in author</li>
  <li>Send author's id (there is a way to request <strong>Profiles</strong> separately)</li>
  </ol>
  
  <p>Which way is faster (in terms on using it on front end) and more convenient (RESTy, if you like).</p>