title: How to add submodule into gh-pages branch & build static pages correctly?
body: <p>I have several project pages to maintain, and all of them use a same theme (I packaged it into a separate repo which called <code>KYProjectPageTheme</code>).</p>
  
  <p>Just copy the <code>KYProjectPageTheme</code>'s entire folder to <code>gh-pages</code> branch's root dir &amp; then push it to Github works very well. I'll receive a notification when static pages build successfully.</p>
  
  <p>However, I want to add <code>KYProjectPageTheme</code> as a submodule under <code>gh-pages</code> branch. This works well in my local machine. But when I pushed it to Github, I could not receive the notification anymore! And static pages are still in the previous state, i.e. modification after I've added a submodule did not affect.</p>
  
  <p>What I guess is that Github's static page generator will not work when there's a submodule in <code>gh-pages</code> branch. But actually, I don't need a generator to generate static pages, I just need to modify pages in HTML &amp; push it to <code>gh-pages</code>. Why not my <code>index.html</code> updated?</p>
  
  <p>Any idea? Is there some workarounds to solve this issue?</p>
  
  <p>Thanks in advance!</p>