title: Commit changes to a submodule without having to commit the parent repo
body: <p>Let's say I have a parent repo <code>myproject</code>, and a separate repo called <code>submodule</code>, with the directory structure that's the following:</p>
  
  <pre>
  
      root$ find . -not -path *.git*
      .
      ./myproject
      ./myproject/submodule
  
  </pre>
  
  <p>Now I add <code>submodule</code> as a submodule to <code>myproject</code>.</p>
  
  <pre>
  
      root$ cd myproject
      myproject$ git submodule add git://url-to-submodule:submodule.git submodule
      Adding existing repo at 'submodule' to the index
  
  </pre>
  
  <p>Now, let's say i change something to <code>submodule</code>.</p>
  
  <pre>
  
      myproject$ cd submodule
      submodule$ touch herpin.txt
      submodule$ add herpin.txt
      submodule$ git commit -am "i'm herpin and i'm derpin"
  
  </pre>
  
  <p>At this point, I go back to the parent repository, and check the git status:</p>
  
  <pre>
  
      submodule$ cd ..
      myproject$ git status
      # On branch master
      # Changes not staged for commit:
      #   (use "git add ..." to update what will be committed)
      #   (use "git checkout -- ..." to discard changes in working directory)
      #
      #   modified:   submodule (new commits)
      #
      no changes added to commit (use "git add" and/or "git commit -a")
  
  </pre>
  
  <p>Well, damn it -- now each time I commit something in submodule, I also have to commit the parent.</p>
  
  <p>It gets annoying pretty quickly if you have a more complex submodule tree. Let's say -- 4-levels deep. If I make a change at the inner-most submodule, I have to commit its parent, its grandparent, its great-grandparent, and its great-great-parent. That's a freaking pain in the ---.</p>
  
  <p>There must be a better way! (And no, not nesting so many levels isn't an option. :/ That's not my call to make ...) Isn't there a way where git-commit can notify the parent repositories of the commit?</p>