title: How to write an update hook for git submodules?
body: <p>I would like to copy some files in the submodules in my "vendor/assets" directory to another directory -- "public/assets." I heard about update hooks but I am not sure if they work for submodules. I wrote a simple hook and ran update from commandline, but it didn't work. </p>
  
  <p>My update hook looks like this:</p>
  
  <pre><code>#.git/gooks/update.rb
  
  #!/usr/bin/env ruby
  
  puts "Copying files..."
  </code></pre>
  
  <p>So is this even possible?</p>
  
  <p>btw, I'm using Braid to manage my submodules.</p>