A few tweaks to the contributors section of the readme.

README.md

@@ -410,16 +410,16 @@ To delete a page and commit the change:
 
 If you'd like to hack on Gollum, start by forking my repo on GitHub:
 
-http://github.com/mojombo/gollum
+http://github.com/github/gollum
 
 To get all of the dependencies, install the gem first. The best way to get
 your changes merged back into core is as follows:
 
 1. Clone down your fork
-1. Create a topic branch to contain your change
+1. Create a thoughtfully named topic branch to contain your change
 1. Hack away
 1. Add tests and make sure everything still passes by running `rake`
-1. If you are adding new functionality, document it in the README.md
+1. If you are adding new functionality, document it in the README
 1. Do not change the version number, I will do that on my end
 1. If necessary, rebase your commits into logical chunks, without errors
 1. Push the branch up to GitHub