Updated the readme for contributing instructions

README.markdown

@@ -1,11 +1,11 @@
 Learn.GitHub.com
 ================
 
-This is the code and data behind [http://learn.github.com]. The page
-content lives in the p/ directory and is compiled into the HTML output
-in pages/. Normally, generated files like these wouldn't be checked into
+This is the code and data behind [learn.github.com](http://learn.github.com). 
+The page content lives in the pages/ directory and is compiled into the HTML 
+output in p/. Normally, generated files like these wouldn't be checked into
 source control, but it's required for the
-[http://pages.github.com/](GitHub Pages) hosting.
+[GitHub Pages](http://pages.github.com/) hosting.
 
 If you edit a page, please remember to run 'rake' to recompile the site
 and create a single commit including both your source and generated
@@ -23,15 +23,22 @@ Once you've done that, just run rake to compile the site:
 
     rake
 
-Last, 
-
-To do: instructions for how to quickly set up a copy of the site on
-GitHub Pages so contributors can see their edits. The info at
-pages.github.com says that it works by repo naming, but forking the repo
-always gives the name 'learn.github.com' and there doesn't seem to be a
-way to rename it (and if there is one, this should be the first
-instruction before people clone their repo). If the users cloned the
-official learn.github.com repo and create their own named repo, the nice
-GitHub features like Pull Requests and the Fork Queue won't work (I
-believe). In short, this instruction needs to be written by a GitHub
-guru/employee.
+
+Contributing
+-----------------------------
+
+To contribute to the learn.github site, you can fork the repository,
+push your changes into it and send a pull request to 'schacon'.  
+
+If you want to run the site on GitHub pages for testing you can push your
+changes into the 'gh-pages' branch, rather than the 'master' branch of
+the remote repository.
+
+  $ git push origin master:gh-pages
+
+That command will push your master branch to the 'gh-pages' branch of
+your fork.  Then Pages will serve the site for you under :
+
+http://schacon.github.com/learn.github.com
+
+(Replace 'schacon' with your username)